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Chemistry Laboratory 3
Creatine Kinase
11
Chemistry
Graduate
11/29/2012

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Term
Kinetic analysis of creatine kinase procedure
Definition
Creatine Kinase reactions occur at zero order kinetics is when the enzyme is the only thing effecting rate, the velocity is constant and there is excess substrate.
Term
The sources of error in the total Creatine Kinase procedure
Definition
interference due to chloride and sulfate contamination, and samples that exceed the maximum range need to be diluted. There was also human sources of error in that the procedure calls for measurements of absorbances at 60 second intervals which is difficult to get perfect.
Term
Quality control
Definition
represented by level 1 and level 2 controls. They have a known value and a reference range. If the reported results are not within the reference range, the patient results cannot be released. They are used to evaluate the accuracy of the procedure, indicating proper technique and performance.
Term
Isoenzyme immunochemical measurement
Definition
we use an antibody for the M monomer of the CK isoenzymes. Isoenzymes are the CK enzymes MM, MB, and BB. They are located in different areas of the body and can be measured as indicators of certain conditions. To measure CK activity we used the presence of an antibody to the CK-M monomer (to measure MM and MB). The antibody inhibits the activity of CK-MM and inhibits half the activity of CK-MB; the concentration multiplied by 2 represents the total activity of the CK-MB activity (which is indicative of a heart attack)
Term
isoenzymes electrophoretically measurement
Definition
To measure isoenzymes electrophoretically you would use an electrophesis gel, which takes longer.
Term
The possible sources of error in the CK-MB procedure
Definition
hemolyzed samples, which are not suitable due to the high levels of adenylate kinase, ATP, and G6P, and overestimation of CK-MB activity if CK-BB activity is high (more then 20% of total activity is represented by CK-MB)
Term
Specimen requirements and storage for the creatine kinase procedure
Definition
A clear non hemolyzed sample is preferred, but plasma in a tube with heprin is acceptable. The serum should be stored at 2-6 degrees C for a max of 5 days.
Term
Why do CK values differ in Male and Females?
Definition
CK values differ due to the average muscle composition difference in men and women. Man have more muscle so therefore their CK levels are higher
Term
Three common methods used for separation and determination of CK isoenzymes?
Definition
Immunochemical method, electrophoretically, and via chromatography
Term
What is Macro CK and why is it formed?
Definition
Macro CK is a macroenzyme formed from the normal CK enzyme and an immunoglobulin. Macro CK doesn't show up differently on the CK assay and could cause an increased reading
Term
Calculation of Total CK activity (U/L)
Definition
(Average change in absorbency/min)/Absorptivity x (total volume (mL)/sample volume (mL))
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