CREATINE PHOSPHOKINASE best slide.pptx

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1. CREATINE PHOSPHOKINASE/CREATINE KINASE (CPK/CK) By : Gunlu Gangmei Regional institute of paramedical and nursing sciences ( RIPaNS ) Msc.MLT (medical biochemistry) Date:26/07/23

2. INTRODUCTION: This enzyme catalyzes the phosphorylation of creatine to form Creatine phosphate by transferring a phosphate group from ATP. REACTION:CREATINE + ATP cpk CREATINEPHOSPHATE + ADP Heart (myocardium), striated muscle and brain (cerebral muscle) have the highest CPK activity. Liver and lungs have negligible CPK content NORMAL VALUE (expected value): at 37 °C Male:46 to 171 U/L Female:24 to 145 U/L

3. cont’d In progressive muscular dystrophy, consistent and marked elevation in serum CPK up to 50-100 times the normal is seen. Serum CPK is also elevated in acute cerebrovascular disease, hypothyroidism , chronic alcoholism. It is not found in RBC cells and its level is not affected by hemolysis.

4. ISOENZYMES Three isoenzymes of creatine phosphokinase are known which are composed of dimers of two subunits: M (muscle) and B (brain): CK-MM (muscle type), CK-MB (heart type) and CK-BB (brain type). Skeletal muscle contains almost exclusively CK-MM, heart contains both CK-MM and CK-MB, while the brain contains CK-BB

5. Isoenzymes cont’d.

6. Isoenzyme cont’d

7. Creatine phosphate + ADP creatine kinase creatine + ATP D-Glucose + ATP hexokinase ADP + Glucose-6- phosphate Glucose-6-phosphate + NADP + G6PD 6-phosphoGluconate + NADPH + H+ The rate of absorbance change at 340nm is directly equal to creatine kinase activity PRINCIPLE:

8. Clinical significance Serum creatinine phosphokinase is increased in myocardial infarction. In progressive muscular dystrophy the increased may be 100 fold even before any clinical sign appears. Increased is also found in to a moderate extent in polymyositis and other muscular dystrophies. Increased values are also found in hypothyroidism with muscle wasting

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