Creatine Kinase Flashcards
What type of strands can creatine kinase be made up of?
M and B
Which strand combinations can be found in which tissues?
MM in muscle and 8% of heart creatine kinase, MB in heart and BB in brain tissue
Why do cells die without oxygen?
They need oxygen for respiration, which provides the energy needed for the sodium pump to work. Without the sodium pump, Na+ will not be pump out of the cell, causing excess water to move into the cell by osmosis and hence causing cell lysis (and death).
Why are the levels of creatine kinase used as an indicator for cell death?
Because when cells die they release their contents due to lysis thus will release creatine kinase, and the type and concentration of creatine kinase can tell you they type and extent of cell death.
Where is creatine kinase usually found?
In cells with a high metabolic activity, as it breaks down creatine phosphate, an energy store.
What and how is measured to indirectly measure creatine kinase and why can this indirectly indicate creatine kinase levels?
NADPH levels, using UV absorption is measured. It works as creatine kinase breaks down creatine phosphate to creatine and ATP. This ATP then reacts with. D-glucose to form ADP and G6P, catalysed by hexokinase. This G6P then reacts with NADP+ to produce NADPH and other things, catalysed by G6P dehydrogenase. Hence, the levels of NADPH are an indicator for the levels of creatine kinase and hence cell death.
What test is done to determine what isoform of creatine kinase is present?
Electrophoresis, as even though the three isoforms have very similar weights, they differ on charge (have different isoelectric points). However, this is a slow procedure so isn’t used in a clinical enviroment.
How is cell death checked in a clinical environment?
Using antibodies which are sensitive/receptive to the MB isoform of creatine kinase, and from there calculating the proportion of all 3 types of creatine kinase, along with other parameters.
