CREATINE KINASE & LACTATE DEHYDROGENASE Flashcards
CREATINE KINASE (CK)
EC
EC 2.7.3.2
CK
Also known as:
Creatine Phosphokinase
ATP:Creatine N-phosphotransferase
CK function
ATP regeneration in contractile or transport system
CK
In muscle cells, it is involved in the storage of_______
Each contraction cycle uses _____to produce ATP
high-energy creatine phosphate
creatine phosphate
TISSUE SOURCE
CREATINE KINASE (CK)
• Highest activities in:
Skeletal muscle
Heart muscle
Brain tissue
TISSUE SOURCE
CREATINE KINASE (CK)
Present in much smaller quantities in:
BKPPP GLLUTS
Bladder
Placenta
Gastrointestinal tract
Thyroid
Uterus
Kidney
Lung
Prostate
Spleen
Liver
Pancreas
CREATINE KINASE (CK)
• More specific indicator of disorders than total CK levels
ISOENZYMES
• CK is a dimer; 2 subunits:
“B” for____ and “M” for____
Brain
Muscle
CK exists as three isoenzymes:
CK-BB (brain type)
CK-MB (hybrid type)
CK-MM (muscle type)
СК-BB (СК1)
Brain
gastrointestinal tract
uterus during pregnancy
not usually measurable in serum due to blood-brain barrier
СК-BB (СК1)
CK-MB (CK2)
Heart muscle
elevated levels indicate myocardial damage
CK-MB (CK2)
CK-MM (CK3)
Striated muscle and normal
serum
primary isoenzyme in skeletal muscle
The major isoenzyme in healthy individuals
Significant in myocardial tissue and a good indicator of myocardial damage
CK-MM (CK3)
ISOENZYMES
CREATINE KINASE (CK)
Atypical CK-isoenzymes
Macro-CK
CK-Mi
Complexes of CK-BB with immunoglobulins, often IgG;
age and sex-related
Macro-CK
Found in muscle, brain, liver;
indicates severe illness
CK-Mi
Which travels fastest to the ANODE
BB
Arrange from most to least fastest
BB
MB
Macro
MM
DIAGNOSTIC SIGNIFICANCE
CREATINE KINASE (CK)
• Elevated in disorders of…
cardiac and skeletal muscle
Increased CK
• Common conditions:
Myocardial infarction (MI)
rhabdomyolysis
muscular dystrophy
CK
• Source of greatest elevation:
Duchenne muscular dystrophy
METHODS OF CK ISOENZYME MEASUREMENT
CREATINE KINASE (CK)
1.) ELECTROPHORESIS
2.) ION-EXCHANGE CHROMATOGRAPHY
3.) IMMUNOINHIBITION
4.) IMMUNOASSAYS
CK
• Reference method
ELECTROPHORESIS
• Advantages:
• Can separate atypical bands, including strongly fluorescent bands near the CK-BB form.
ELECTROPHORESIS
Detects unsatisfactory separations and allows visualization of adenylate kinase (AK), which can interfere with chemical or immunoinhibition methods.
ELECTROPHORESIS
2.)ION-EXCHANGE CHROMATOGRAPHY
Procedure:
This method uses_____ to separate____
ion-exchange columns
CK isoenzymes.
Advantages:
Potentially more sensitive and precise than electrophoresis.
ION EXCHANGE CHROMATOGRAPHY
IEC
Disadvantages:
On an unsatisfactory column, _____may merge into_____, and _____may elute with_____.
Additionally,_____ can also elute with____, causing inaccuracies.
CK-MM -> CK-MB
CK-BB -> CK-MB
macro-CK -> CK-MB
Antibodies target M and B subunits to measure CK-MB activity.
IMMUNOINHIBITION
Anti-M antibodies inhibit M activity but not B activity.
IMMUNOINHIBITION
IMMUNOINHIBITION
CK activity is measured_____
Remaining activity post-inhibition indicates B subunit activity.
Residual activity is doubled to account for MB (50% inhibited).
BB activity detection can falsely elevate MB results.
before and after M inhibition
IMMUNOINHIBITION
_________ are not inhibited, causing potential errors.
Atypical forms (CK-Mi, macro-CK)
This leads to the possibility of permitting detection of infarction earlier than other methods.
IMMUNOASSAYS
Measure the concentration of enzyme protein rather than enzymatic activity and can, therefore, detect enzymatically inactive CK-MB.
IMMUNOASSAYS
Detect CK-MB reliably with minimal cross-reactivity.
IMMUNOASSAYS