Clinical Significance of Enzymes PDF

Almaaqal University Clinical significance of enzymes Dr/ Wael Sobhy Darwish Biochemistry PhD Lec-4  Plasma Enzymes Blood plasma contains many enzymes , which are classified into functiona...

Almaaqal University Clinical significance of enzymes Dr/ Wael Sobhy Darwish Biochemistry PhD Lec-4  Plasma Enzymes Blood plasma contains many enzymes , which are classified into functional and non functional enzymes. Functional enzymes present at all times in the circulation and perform a physiologic function in the blood , examples of these functional enzymes include lipoprotein lipase , pseudocholinestrase and enzymes of blood coagulation. These enzymes are synthesized and secreted by the liver.  Non functional enzymes Plasma also contains numerous other enzymes that perform unknown physiologic function in blood. These non functional plasma enzymes arise from the routine normal destruction of erythrocytes , leukocytes , and other cells. Tissue damage or necrosis resulting from injury or disease is generally accompanied by increasing in the levels of several non functional plasma enzymes. Therefore several enzymes are used in the diagnosis.  Sources of non-functional plasma enzymes 1. Increase in the rate of enzyme synthesis e.g. bilirubin increases the rate of synthesis of alkaline phosphatase in obstructive liver diseases. 2. Increased permeability of cell membrane as in tissue hypoxia. 3. Cell damage with the release of its content of enzymes into the blood e.g. myocardial infarction and viral hepatitis.  Medical importance of non functional plasma enzymes. Measurement of non functional enzymes is important for : 1- Diagnosis of diseases as diseases of different organs cause elevation of different plasma enzymes. 2- Prognosis of the diseases : we can follow up the effect of treatment by measuring plasma enzymes before and after treatment.  Enzymes of diagnostic values 1) Use of enzymes as reagents for determination of normal and pathological components in serum, urine, gastric juice etc. 2) Determination of enzyme activity in biological material with a diagnostic purpose. Amylase Amylase breaks down starch and glycogen to maltose.  It is present at high concentrations in pancreatic juice and in saliva. The plasma activity of this enzyme is very high in acute pancreatitis. Lipase: It is found in the pancreas. Increased amounts of this enzyme indicates disease and inflammation of the pancreas. Aspartate Amino Transaminase (AST) and Alanine Amino Transaminase (ALT).  Both the enzymes are present in heart, liver, skeletal muscle, kidney and erythrocytes. Damage to any of these tissues may increase plasma level of these enzymes. Myocardial infarction· Acute viral or toxic hepatitis·  Liver fibrosis and cirrhosis· Acid Phosphatase (ACP)  This enzyme is present in high concentrations in the prostate gland, liver, rbc, platelets and bone.  And it is elevated in the plasma of some patients with prostatic cancer. Lactate Dehydrogenase (LDH)  This enzyme is present in all cells of the body.  Serum LDH is increased in liver, heart, skeletal muscle and kidney diseases, and neoplastic disease.  Alkaline phosphatase It catalyzes the hydrolysis of organic phosphate esters, optimally at alkaline pH. Phosphate is necessary for the formation of bone and teeth. It seems to be important in the formation of mineralized tissues. Alkaline phosphatase levels were increased in various disease processes like periodontitis, gingivitis, and bone disorders. Creatine Kinase Creatine kinase consists of two protein sub units (dimer) M and B, which combine to form three isoenzymes(BB, MM and MB).  Enzymes and dentistry Enzymes play a significant role in dentistry, particularly in the field of oral biology and oral health. Salivary Enzymes: Saliva contains several enzymes that are crucial for maintaining oral health. Amylase helps break down complex carbohydrates into simpler sugars, initiating the digestion process. Lysozyme, an enzyme found in saliva, exhibits antimicrobial properties by attacking the cell walls of bacteria, contributing to the defense against oral infections. Salivary peroxidase and lactoperoxidase are enzymes involved in the antibacterial activity of saliva, helping to protect against oral pathogens.  Enzymes in Dental Diagnosis: Enzyme biomarkers can be used for diagnosing oral diseases. For instance, elevated levels of certain enzymes like alkaline phosphatase and aspartate aminotransferase in saliva can indicate periodontal disease. Enzyme-based tests, such as measuring the activity of matrix metalloproteinases (MMPs), can be used to assess the breakdown of connective tissues in oral diseases like periodontitis. Enzymes in Dental Materials: Enzymes are involved in dental materials and procedures. For example, enzymes like papain and bromelain are used to break down surface proteins and aid in the removal of the impression from the oral cavity. Enzymes are also used in denture cleansers to remove biofilm and prevent bacterial colonization on dentures. Enzymes and Dental Caries:  Dental caries (tooth decay) is caused by the demineralization of tooth structures due to bacterial acid production. Enzymes produced by oral bacteria, such as glucosyltransferases, contribute to the formation of dental plaque and the initiation of caries.  Enzymes in Periodontal Therapy: Enzymatic therapy is used as an adjunct to periodontal treatment. Enzymes like collagenase are used in locally applied gels to break down collagen fibers within periodontal pockets, facilitating the removal of diseased tissue and promoting periodontal healing. Enzymes like hyaluronidase can be used to enhance the effectiveness of local anesthetics by facilitating their diffusion into tissues.