(20) CK - MI PROFILE Flashcards
- Involved in the storage of high-energy creatine phosphate in muscle cells
Creatine Kinase (CK)
CK structure
Dimeric enzyme
o Has 2 monomer subunits (can either be “M” or “B” subunits)
- Widely distributed, highest activities in skeletal muscle, heart, & brain
o Not heart-specific
CK
- Migrate fastest toward the anode (closest to anode)
- Highest conc. in CNS, GI tract, & uterus (pregnancy)
- ↑↑in CSF leakage (BBB damage)
CK-1
CK-BB
BRAIN TYPE
- 2nd fastest to migrate toward the anode
- Significant quantities are found in heart tissues
CK-2
CK-MB
HYBRID TYPE
- Slowest mobility toward the anode
- Major isoenzyme in striated muscle & normal serum
- Predominant CK isoenzyme in blood.
CK-3
CK-MM
MUSCLE TYPE
▪ CK enzyme is combined w/ Abs or lipoproteins
▪ Migrate between CK-MM & CK-MB in electrophoresis
Ex.
* CK-BB has either IgG or IgA
* CK-MM has lipoproteins
Macro-CK
▪ Bound to mitochondrial membrane
▪ Migrates cathodal to CK-MM
▪ ↑CK-Mi indicates a more severe cell injury
Mitochondrial CK (CK-Mi)
Diagnostic Significance of CK isoenzymes:
After MI, CK-MB (>6%) levels begin to rise within ____, peaks @ ____, & returns to normal levels within ____.
After MI, CK-MB (>6%) levels begin to rise within 4-8hrs, peaks @ 12-24hrs, & returns to normal levels within 48-72hrs.
Tests for CK:
▪ Specific isoenzyme is the target
▪ More diagnostic
CK isoenzyme
Tests for CK:
▪ Activity of all CK isoenzymes are measured
Total Ck
CK Methods:
▪ ↓in absorbance @340nm is determined (oxidized NAD is measured)
▪ Optimum pH is 9.0
▪ Coupling / indicator / 2ndary enzyme: PK & LDH
Tanzer-Gilvarg
CK Methods:
▪ ↑in absorbance @340nm is determined (reduced NADH is measured)
▪ Optimum pH: 6.8
▪ Coupling / indicator / 2ndary enzyme: HK & G6PD
Oliver-Rosalki
Forward rxn – left to right
Tanzer-Gilvarg
Reverse rxn – right to left
Oliver-Rosalki
