Enzyme Markers: Purpose, Procedure, and Results

What are enzyme markers?

Enzymes are highly specialized complex proteins that aid chemical changes in every part of the body. For example, they help break down food so your body can use it effectively. They also help your blood clot. And they’re present in every organ and cell in your body. Enzymes are necessary for your body to function properly.

Enzyme markers are blood tests that analyze specific enzyme activity in the body. Some inherited diseases or conditions can cause these enzymes to stop working or be less efficient. Monitoring the rise or fall of enzyme levels can aid in the diagnosis of a variety of conditions.

Your doctor can order a blood test for enzyme markers, or a routine blood test to help uncover abnormalities. In some cases, you may need to take a test multiple times over the course of several days to measure changes over time.

CPK isoenzymes

The CPK isoenzymes test measures the creatine phosphokinase (CPK) in the blood. CPK enzymes are in the heart, brain, and skeletal muscles. Normal CPK levels vary by age, gender, and race.

Each laboratory may have minor differences in reference ranges, as well. In general, a CPK level of approximately 200 units per liter (U/L) or less is considered normal in an adult. This is the total CPK level in your body. More specific testing can be done, but this is not routine.

Read more: CPK isoenzymes test »

CPK-1 resides mostly in the brain and lungs. Increased levels of CPK-1 can be due to:

• brain cancer
• brain injury, stroke, or bleeding in the brain
• pulmonary infarction, which is the death of lung tissue
• seizure
• electroconvulsive therapy

CPK-2 levels rise following a heart attack. Increased levels of CPK-2 may also be due to:

• open heart surgery
• inflammation of the heart muscle
• heart injury
• defibrillation
• electrical injuries
• chest compressions after cardiac arrest

High CPK-3 levels can be a sign of muscle stress, a crush injury, or injury due to:

• muscle damage, dystrophy, or inflammation
• intramuscular injections
• electromyography, which is a muscle and nerve function test
• recent surgery
• seizures
• strenuous exercise

Heart enzymes

Some heart enzymes slowly enter your blood if you’ve had a heart attack and your heart is damaged as a result. A general test for emergency room patients with heart attack symptoms is a test for the presence of certain proteins in your blood. A doctor may check CPK-2, also known as CK-MB. This marker is highly specific for heart muscle injury and rises rapidly during a heart attack. Normal CK-MB should be between 5-25 international units per liter (UI/L).

The preferred marker of heart injury, though, is a protein called troponin. Troponin should generally be less than 0.02 nanograms per milliliter (ng/mL). The level takes longer to rise than CK-MB, but the protein stays in the bloodstream longer.

Learn more: Symptoms of a heart attack »

Liver enzymes

Elevated liver enzymes may be due to inflammation or damaged liver cells. Usually, elevated liver enzymes are related to an acute injury, or a process that occurred over a short period of time due to:

• prescription medications, such as statins
• over-the-counter (OTC) medications, such as acetaminophen (Tylenol)
• alcohol consumption
• heart failure or heart attack
• liver disease, such as hepatitis, fatty liver disease, cancer, and cirrhosis
• obesity
• celiac disease, which is a digestive condition
• viruses, such as cytomegalovirus infection; hepatitis A, B, C, E viruses; mononucleosis; and Epstein-Barr virus
• inflammatory diseases, such as dermatomyositis, pancreatitis, and gallbladder inflammation
• muscular diseases, such as muscular dystrophy or polymyositis
• ischemia, or lack of oxygen going to the liver, such as during cardiac arrest
• hemochromatosis, which is a disorder in which there’s too much iron in the blood
• underactive thyroid
• Wilson disease, which is a disorder where there’s too much copper stored in the body
• physical trauma to the organ

There are several markers that can be used to test liver function. These markers help separate whether or not the injury is to the liver parenchyma (liver cells) or to the biliary system. For the purposes of this article, the important tests are the liver aminotransferases: alanine aminotransferase (ALT) and aspartate aminotransferase (AST).

ALT is primarily produced by the liver, while AST can be from the liver, cardiac muscle, skeletal muscle, kidney, and brain. A normal ALT level is 29-33 IU/L for men, and 19-25 IU/L for women. A normal AST level may range from 10-40 IU/L for men and 9-32 IU/L for women.

These reference ranges vary from hospital to hospital. It’s important to compare your liver enzyme levels to the reference ranges provided by the lab.

The test is a routine blood test that takes place in a laboratory. No fasting or special preparation is necessary. But tell your doctor before the test about all prescription and OTC medications and supplements you take.

A blood test involves the following steps:

• A healthcare provider will use an antiseptic to clean a small area of your arm, usually the inside of your elbow or the back of your hand.
• They’ll then wrap an elastic band around your upper arm to create pressure and make it easier to access a vein.
• They’ll insert a needle into your vein and blood will flow into a small vial. You’ll likely feel the stick of the needle or a stinging sensation.
• After filling the vial, the healthcare provider will remove the elastic band and the needle.
• They’ll place a bandage over the puncture site and send the blood sample to a lab for analysis.
• The procedure should take only a few minutes.

Your arm may be sore at the puncture site, and you might have some mild bruising or brief throbbing.

Most people have no serious or lasting side effects from a blood test. Rare complications include:

• bleeding
• lightheadedness
• fainting
• infection, which is a small risk whenever the skin is broken

Contact your doctor immediately if you have any of these symptoms.

Abnormal test results can indicate a variety of problems from disease to a simple muscle strain because enzymes are present in every cell of your body. Your doctor will be able to determine a proper course of treatment based on your exact enzyme marker levels and the symptoms you’re having.

Aspartate aminotransferase (AST) blood test Information | Mount Sinai

Aspartate aminotransferase; Serum glutamic-oxaloacetic transaminase; SGOT

The aspartate aminotransferase (AST) blood test measures the level of the enzyme AST in the blood.

Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

No special preparation is needed.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

AST is an enzyme found in high levels in the liver, heart, and muscles. It is also found in lesser amounts in other tissues. An enzyme is a protein that causes a specific chemical change in the body.

Injury to the liver results in release of AST into the blood.

This test is mainly done along with other tests (such as ALT, ALP, and bilirubin) to diagnose and monitor liver disease.

Normal Results

The normal range is 8 to 33 U/L.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your health care provider about the meaning of your specific test results.

What Abnormal Results Mean

An increased AST level is often a sign of liver disease. Liver disease is even more likely when the levels of substances checked by other liver blood tests have also increased.

An increased AST level may be due to any of the following:

• Scarring of the liver (cirrhosis)
• Death of liver tissue
• Heart attack
• Too much iron in the body (hemochromatosis)
• Swollen and inflamed liver (hepatitis)
• Lack of blood flow to the liver (liver ischemia)
• Liver cancer or tumor
• Use of drugs that are toxic to the liver, especially alcohol use
• Mononucleosis (“mono”)
• Muscle disease or trauma
• Swollen and inflamed pancreas (pancreatitis)

AST level may also increase after:

• Burns (deep)
• Heart procedures
• Seizures
• Surgery

Pregnancy and exercise may also cause an increased AST level.

Risks

There is little risk involved with having your blood taken. Veins vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.

Risks associated with having blood drawn are slight, but may include:

• Fainting or feeling lightheaded
• Excessive bleeding
• Multiple punctures to locate veins
• Hematoma (blood collecting under the skin)
• Infection (a slight risk any time the skin is broken)

Daniels L, Khalili M, Goldstein E, Bluth MH, Bowne WB, Pincus MR. Evaluation of liver function. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 22.

Pratt DS. Liver chemistry and function tests. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran’s Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 73.

Last reviewed on: 2/28/2023

Reviewed by: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Enzymes contained in gastric juice: their role and functions

Gastric juice contains the enzyme pepsin, which plays a key role in the process of protein digestion. Learn how pepsin works and how its activity helps the body break down food.

Gastric juice plays an important role in the human digestive process. It contains various enzymes that perform key functions in the breakdown of food. Enzymes are proteins that speed up chemical reactions in the body. There are several main enzymes in the gastric juice, each of which performs its own specific task.

One of the main enzymes in gastric juice is pepsin. It is responsible for the decomposition of proteins into simpler components – peptides and amino acids. Pepsin is active in the acidic environment of the stomach, where it converts the proteins in food into a soluble form so they can be absorbed by the body.

Another important enzyme is lipase. It is responsible for the breakdown of fats into glycerol and fatty acids. Lipase acts on fats that enter the stomach from food, as well as on fats that are secreted by bile from the liver. Lipase breaks down fats into smaller molecules so that they can be absorbed by the body.

In addition, gastric juice contains a number of other enzymes, such as amylase, which breaks down carbohydrates, and gastrin, a hormone that stimulates the secretion of gastric juice. All of these enzymes work together to ensure efficient digestion and nutrient absorption by the body.

Thus, the enzymes contained in the gastric juice play an important role in digestion. They help break down food into simpler components that can be absorbed by the body. Thanks to these enzymes, efficient digestion occurs and nutrients can be absorbed by the body to maintain its functions and health.

Enzymes in gastric juice: why are they needed?

Enzymes in gastric juice play an important role in the process of digestion. They help break down food into simpler components that the body can absorb and use for energy and nutrients.

One of the main enzymes found in gastric juice is called pepsin. This enzyme is responsible for breaking down proteins into amino acids. It is active in the acidic environment of the stomach and is able to break down complex protein structures into simpler parts.

In addition to pepsin, other enzymes such as lipases and amylases are also present in gastric juice. Lipases are responsible for breaking down fats into glycerol and fatty acids, while amylases break down complex carbohydrates into simple sugars.

Enzymes in the gastric juice play a key role in the processing of food and the proper functioning of the body. Without them, food could not be fully digested and used by the body. Therefore, maintaining the health of the gastrointestinal tract and the normal functioning of enzymes is important for maintaining overall well-being and health.

The role of enzymes in digestion

Enzymes play an important role in the body’s digestive system, helping to break down food into simpler components that can be absorbed and used by the body. Enzymes are proteins that catalyze chemical reactions, speeding them up. The gastric juice contains various enzymes that perform certain functions in the process of digestion.

One of the main enzymes contained in gastric juice is pepsin. Pepsin is responsible for breaking down proteins into simpler amino acids. It is active in the acidic environment of the stomach and is able to break bonds between amino acids in proteins, which allows them to be easily absorbed by the body.

Another enzyme found in gastric juice is lipase. Lipase is responsible for the breakdown of fats into glycerol and fatty acids. This process allows the body to absorb and use fat as an energy source.

In addition, amylase is present in the gastric juice, which decomposes carbohydrates into glucose molecules. This allows the body to absorb and use carbohydrates as an energy source.

Thus, the enzymes contained in gastric juice play an important role in the process of digestion, breaking down food into simpler components that can be absorbed and used by the body. They perform specific functions by breaking down proteins, fats and carbohydrates into simpler molecules, which allows the body to receive the necessary nutrients to sustain life.

The most important enzymes of gastric juice

Gastric juice is one of the key factors in the process of digestion. It contains various enzymes that play an important role in breaking down food and ensuring efficient absorption of nutrients.

One of the main enzymes of gastric juice is pepsin. It is responsible for breaking down proteins into simpler components such as amino acids. Pepsin actively works in the acidic environment of the stomach and is a key factor in the digestive process.

In addition to pepsin, gastric juice also contains gastrin, gastroxin and secretin. Gastrin stimulates the release of hydrochloric acid, which creates an acidic environment in the stomach and promotes the activation of pepsin. Gastroxin regulates the motor activity of the stomach and is involved in the production of hydrochloric acid. Secretin regulates the secretion of gastric juice and maintains optimal pH in the stomach.

Another important enzyme found in gastric juice is lipase. It is responsible for the breakdown of fats into glycerol and fatty acids, which ensures their absorption by the body. Lipase acts in the alkaline environment of the duodenum, which is formed due to the release of secretin and other enzymes.

Each of these enzymes has a unique function in the digestive process. The interaction between them ensures the efficient breakdown of food and the absorption of nutrients by the body.

Pepsin: the main enzyme for protein breakdown

Pepsin is one of the main enzymes found in gastric juice. Its main function is to break down proteins into simpler components such as peptides and amino acids. Thus, pepsin plays an important role in the process of digestion, ensuring the breakdown of proteins at the molecular level.

The action of pepsin begins in the stomach, where it actively works in an acidic environment. Pepsin is able to break proteins into smaller fragments, which facilitates their further assimilation by the body. This is especially important, since proteins are the main source of amino acids necessary for the synthesis of new proteins and for the normal functioning of the body.

Pepsin is produced in the stomach in an inactive form called pepsinogen. Under the action of hydrochloric acid secreted by the stomach, pepsinogen is converted into active pepsin. This mechanism is important because it prevents damage to the gastric mucosa by pepsin in an inactive form.

The use of pepsin in industry also has its uses. It can be used to break down proteins in foods such as meat and milk to produce a variety of products and ingredients. Pepsin is also used in laboratory research to study the properties and structure of proteins.

Lipase: an enzyme responsible for the breakdown of fats

Lipase is an enzyme that plays an important role in the breakdown of fats in the body. It performs the function of hydrolyzing fatty molecules, breaking them down into the smallest components – glycerol and fatty acids. Thus, lipase ensures the efficient absorption and processing of fatty substances in the body.

Lipase is present in gastric juice and performs its function in the process of digestion. She is actively involved in the breakdown of fats that enter the stomach with food. Fatty molecules that have not been hydrolyzed are more difficult for the body to digest and can cause various digestive problems.

Lipase is highly specific and only effective on fats. It breaks down fatty molecules that are made up of glycerol and fatty acids. The process of splitting fats occurs in several stages, starting with the action of lipase in the stomach and ending with the final processing of hydrolysis products in the intestines.

Lipase plays a key role in the body’s metabolism and energy supply. It ensures the normal functioning of the digestive system and the absorption of fats necessary for the body. Thanks to lipase, the body receives the energy necessary to perform all vital processes.

Amylase: an enzyme for the breakdown of carbohydrates

Amylase is one of the main enzymes found in gastric juice. Its main role is to break down carbohydrates such as starch and glycogen into simpler sugars. This process is called hydrolysis and allows the body to efficiently absorb carbohydrates, which are an important source of energy for the body.

Amylase begins its work already in the oral cavity, where it continues the decomposition of starch into maltose and dextrin. It then passes into the stomach, where it continues its activity for a short time until it is inactivated by gastric juice. The final breakdown of carbohydrates occurs in the small intestine with the help of other enzymes such as maltase and lactase.

Amylase has several forms in the body, including alpha-amylase and beta-amylase. Alpha amylase is the most common and works on starch and glycogen, breaking them down into maltose and dextrin. Beta-amylase, in turn, decomposes starch into maltose. Both of these enzymes are important for normal carbohydrate digestion and providing the body with essential nutrients.

The role of enzymes in digestion

Enzymes play an important role in the digestion process, ensuring that food is broken down to the molecular level and absorbed by the body. They are biological catalysts that speed up chemical reactions without participating in them directly.

Gastric juice contains several enzymes that perform different functions. One of them, pepsin, promotes the decomposition of proteins into simpler amino acids. It is active in the acidic environment of the stomach and helps break down food into particles that can be absorbed by the body.

Another enzyme, lipase, breaks down fats into glycerol and fatty acids. It is also present in gastric juice and plays an important role in the process of fat digestion.

Amylase is another enzyme found in gastric juice that breaks down polysaccharides such as starch and glycogen into glucose molecules. This allows the body to absorb carbohydrates from food and use them as an energy source.

Thus, the enzymes in the gastric juice play an important role in the process of digestion, ensuring the breakdown of food into simpler components that can be absorbed by the body. This allows the body to receive the necessary nutrients and keep it working.

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Q&A:

What enzymes are found in gastric juice?

Gastric juice contains several enzymes, the main ones being pepsin and hydrochloric acid.

What role do enzymes play in gastric juice?

Enzymes in gastric juice play an important role in digestion. They help break down proteins into smaller components, making them easier for the body to absorb.

What functions does pepsin perform in gastric juice?

Pepsin is the main enzyme of the gastric juice, which is responsible for the breakdown of proteins into peptides and amino acids. It is active in the acidic environment of the stomach and is able to break peptide bonds in proteins, making them more available for further cleavage.

What role does hydrochloric acid play in gastric juice?

Hydrochloric acid has several functions in gastric juice. First, it creates an acidic environment, which is necessary for the activation of pepsin. Secondly, it kills most bacteria and other microorganisms that can enter the stomach with food. Finally, it helps soften food and make it easier to break down.

What other enzymes are present in gastric juice?

In addition to pepsin, other enzymes such as gastrin and somatostatin are also present in gastric juice. Gastrin stimulates the production of gastric juice, and somatostatin, on the contrary, reduces it. These enzymes regulate the digestive process and keep it functioning optimally.

The effect of enzymes on the general condition of the body

Enzymes contained in gastric juice play an important role in the human body and affect its general condition.

The first effect of enzymes on the body is related to the process of digestion. Gastric enzymes such as pepsin, trypsin, and chymotrypsin break down proteins into simpler compounds called amino acids. This allows the body to receive the necessary nutrients and energy to maintain its vital functions. If the digestion process is disturbed due to lack of enzymes or other causes, it can lead to various health problems such as nutritional deficiencies, metabolic disorders, and even the development of diseases.

The second effect of enzymes on the body is related to the immune system. Certain enzymes, such as lysozyme, help protect the body from infections. Lysozyme breaks down the cell walls of bacteria, making them vulnerable to further destruction by the immune system. In addition, enzymes are involved in the regulation of inflammatory processes in the body. A malfunction of the immune system or a lack of certain enzymes can lead to increased inflammatory activity and various diseases.

The third effect of enzymes on the body is related to metabolism. Enzymes play an important role in the body’s metabolic processes, such as the synthesis and breakdown of molecules. For example, enzymes are involved in the formation of glucose from carbohydrates, the synthesis of fats and proteins. They are also involved in breaking down excess or damaged molecules, helping the body get rid of toxins and metabolic waste. Violation of the work of enzymes can lead to metabolic disorders and the development of various pathological conditions, such as obesity, diabetes, and others.

Thus, the enzymes contained in the gastric juice have a significant impact on the general condition of the body. They ensure the normal process of digestion, protect the body from infections, regulate metabolism and support its vital functions. It is important to maintain the balance of enzymes in the body and ensure that they are sufficient to maintain health and well-being.

How to keep gastric juices and enzymes healthy?

Gastric juice and enzymes play an important role in the digestive process. To keep them healthy and effective, there are a few key things to keep in mind.

Proper nutrition: The diet should be balanced and contain sufficient nutrients. It is important to eat a variety of foods, including vegetables, fruits, grains, proteins, and healthy fats. Avoid excessive consumption of fatty and fried foods, which can cause gastric acid overload.

Regular meals: Divide your diet into several small meals throughout the day. This will help reduce the load on the gastric juice and facilitate digestion. Try not to eat before bed to give your body time to digest the food.

Moderation in alcohol and caffeine intake: Avoid excessive alcohol and caffeine intake as they can irritate the stomach and impair enzyme function. If you have stomach problems, you should limit your intake of these drinks.

Avoid stress: Stress can affect the functioning of gastric juices and enzymes. Try to engage in regular relaxation practices such as yoga or meditation to reduce your stress levels.

Drink enough water: Water plays an important role in digestion and helps to maintain optimal functioning of gastric juices and enzymes. It is recommended to drink at least 8 glasses of water throughout the day.

Moderate exercise: Regular moderate exercise helps to normalize the work of gastric juice and enzymes. They help improve blood circulation and enhance digestion.

Avoid smoking: Smoking affects the health of gastric juices and enzymes. It can cause irritation of the gastric mucosa and reduce the activity of enzymes. Therefore, it is recommended to avoid smoking and passive smoking.

Following these guidelines will help maintain healthy gastric juices and enzymes, which in turn promotes normal digestion and overall health.

Diagnosis of pancreatitis – blood test for lipase and amylase

Amylase and lipase are digestive enzymes. Their amount in the bloodstream is used to diagnose the condition of the pancreas in case of suspected pancreatitis. Analyzes can be carried out at the direction of a doctor or at the request of the patient, but only a specialist can interpret the results and, if necessary, prescribe treatment. To obtain the most accurate results, special preparation is required before donating blood. Within 10 hours before the tests, it is necessary to refuse to eat food, avoid significant physical exertion, stress.

Lipase test

Lipase is an enzyme that is necessary for the breakdown of fats. The results of a blood test for lipase play an important role in the diagnosis of diseases such as obstruction of the pancreatic duct and pancreatitis in acute or chronic form. Reference values ​​for this enzyme are 13-60 IU/L. If the test results are within these values, this indicates that at the moment the pathological process does not affect the pancreas.

Elevated levels of may indicate acute or chronic inflammation, neoplastic changes, traumatic injury to the pancreas, blockage of its ducts. Based on the results of one test, it is impossible to make an accurate diagnosis and choose an effective treatment method. For this, an examination is prescribed, which may include both laboratory tests and instrumental studies.

Concentration too low enzyme in the blood may indicate a decrease in the functional activity of the pancreas or cystic fibrosis.
Determining the level of lipase has a high diagnostic value in identifying various pathologies of the pancreas. The enzyme is produced only by the cells of this organ, so it can be used as a marker of its condition.

When interpreting the results, the patient’s age, clinical picture, results of other studies and other factors are taken into account.

Amylase test

Amylase is an enzyme responsible for the breakdown of carbohydrates. It, unlike lipase, is produced not only by the pancreas, but also by the salivary glands. In addition, a certain amount of the enzyme is formed in the skeletal muscles, intestines and ovaries. A blood test for amylase is prescribed for patients with acute or chronic pancreatitis, with suspicion of pathology of the ovaries or salivary glands.

In patients over 18 years of age, the enzyme level should not exceed 53 U / l.