7 -Enzyme in Clinical Practice

8/6/2019 7 -Enzyme in Clinical Practice

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Lecture 7

Enzymes in clinical practiceBy Dr Nivan Zoheiry



Overview

Reactions in human body is mediatedby enzymes, which are Globular

protein catalysts that increase the rateof the reactions without being changedin the overall process



Clinical Uses of Enzymes

Enzymes are used clinically in threeprincipal ways:

1-In diagnosis and prognosis of variousdisease

2-As analytical reagents in the measurementof activity of other enzyme or non-enzyme

substances

3-As therapeutic agents



Isoezymes

Isoezymes: are different formes of givenenzyme having the same catalytic activity, but differ in some physical or chemicalproperties.

Thus each isoenzyme will act on the samesubstrate and give the same product.

LDH, ALP and CPK are enzymes havingisoenzymes.





Enzymes as Therapeutic Agents

Some enzymes are used in treatment of certaindiseases.

1-Digestive enzymes

,

2-Anti-inflammatory agents that reduce swellingand help clear away debris. Papain also hasanalgesic and anti-inflammatory action.

3-Pancreatic enzymes do have a powerful anti-cancer effect on pancreatic cancer and multiplemyleoma.



4- Streptokinase is a enzyme produced by

beta-haemolytic streprococus and is used asan effective clot-dissolving medication insome cases of myocardial infarction andpulmonary embolism

Defective enzyme can result from geneticmutation, or infection by bacteria or viruses,The development of Enzymereplacement therapy (ERT) has brought

hope to individuals with some rare, inheriteddiseases.



ERT

ERT is not a cure for any condition; but ittreats the deficient enzyme activity.

ERT is safe and effective; however , it iscostly



Diagnosis and Prognosis Destruction of cells. Tissue damage or

necrosis resulting from injury or disease isaccompanied by increase in levels of enzymes.

By measuring the level of certain enzymesin plasma it helpes in the diagnosis andprognosis of many diseases

Isozymes of lactate dehydrogenase (LDH) areused in MI diagnosis

Creatinine kinase (CK) used MI and Muscledisorders



Enzymes which may indicate alterations inliver health.

Alanine Aminotransferase: ALT Cell damage will cause elevations of A-LTdue to leakage. The elevation of the enzymecorrelates with the number of cellsdamaged.

Falling levels of ALT may indicate recoveryor may indicate a failing number of

functional liver cells. Rapid increases in ALT may indicate an

acute process, while slow increases mayindicate bile duct obstruction.



Aspartate Aminotransferase: AST

enzyme seen in the liver , heart, kidney, skeletal muscle and brain, AST elevations and ALT elevations should parallel each other inliver disease

Alkaline Phosphatase ALPThis enzyme is present in many tissues,

therefore it is not very specific in liver disease, but it appears very early in the progress of liver

disease, therefore it is considered quitesensitive





Site-directed mutagenesis

Site-directed mutagenesis has been widelyused in the study of protein functions.

There are many approaches were amutation being added to DN A strand in acertain site

Site-directed mutagenesis (modification of

amino acid sequence of known enzymes) isused for design new drug therapy



Ribozymes and catalytic

antibodies Abzymes - Abzymes are antibodies thatcatalyze specific chemical reactions, i.e.function as enzymes.

Antibodies by definition have evolved torecognise and bind to the ground states of the molecules they are specific to. Incontrast, enzymes have binding sites that

preferentially bind to the transition state of their substrate molecules

For this reason abzymes are not producednaturally



Ribozymes

Ribozymes are RN A molecules withcatalytic activity.

And concerned with RN A metabolism as

splicing In higher eukaryotic cells, show that RN A

can act as an enzyme. This hasrevolutionized thinking about enzyme action

and the origin of life itself.

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7 -Enzyme in Clinical Practice