Creatine Kinase Flashcards
What is creatine kinase used for?
To convert creatine phosphate into Creatine and ATP
Where in the body is creatine kinase found in particularly high concentrations?
in the brain and muscle cells
When is creatine kinase released into the circulation?
Following death / damage of brain and muscle cells
How many isoforms are there of creatine kinase?
Three isoforms - can be identified through gel electrophoresis
What are the three isoforms of creatine kinase?
MM, MB and BB
What is the only place in which the MB isoform is found?
Cardiac muscle
Which isoform moves closest to the negative electrode?
MM isoform
What is myocardial infarct?
death of heart muscle cells
What might cause a lack of oxygen resulting in a myocardial infarct?
Blockage of the cardiac arteries. This process is termed atherosclerosis and you might like to ponder on what kind of things might be risk factors for its early development.
Why do cells need oxygen, how do they use it and why do cells die without it?
ATP is generated Via glycolysis, the Krebs Cycle and eventually oxidative phosphorylation.
The end point of the process requires atmospheric oxygen, hence if there is less oxygen supplied to a cell there is less ATP, pumps do not function, ion balance is lost and cells die.
Why can the levels of proteins inside the blood be used to indirectly indicate cell death?
Cellular contents are released from cells when they are dying eg proteins which shuld be held against concentration gradients appear in the serum - Therefore the levels of many proteins including creatine kinase (many others as well such as lactate dehydrogenase) in serum can be used as indirect indicators of cell death.
Describe the absorption spectrum for NADH and NAD+?
They are distinct
What technique is used to detect CK activity in the serum?
coupled assay
How then can increased CK be related specifically to the death of cardiac muscle rather than skeletal muscle and brain tissue?
The only tissue where both genes are expressed is cardiac muscle cells. They therefore make all three dimers including the hybrid MB form.
Thus, death of cardiac muscle fibres can be determined if the MB isoform of CK can be detected in the serum.
Which form of creatine kinase is only expressed in the brain?
BB isoform as the brain only expresses the B gene
