M.I. PROFILE/ CARDIAC MARKERS/ CARDIAC ENZYMES Flashcards
Involved in the storage of high-energy creatine phosphate in muscle cells
: Creatine Kinase (CK)/ Creatine Phosphokinase
when creatine phosphate is consumed during muscle metabolism →
creatinine is generated
Creatinine is excreted at a _______ by the glomerular membrane
constant rate
CK is _______ . It is widely distributed, highest activities in _____, _____, _____, and _____
NOT HEART SPECIFIC
skeletal muscle, heart, and brain
Creatine kinase would transfer 1 phosphate group from ___ to creatine to form ______ and ___
ATP, Creatine phosphate and ADP
Creatine Kinase (CK)/ Creatine Phosphokinase substrates
Creatine & ADP
Creatine Kinase (CK)/ Creatine Phosphokinase
products
Creatine Phosphate & ADP
Creatine Kinase (CK)/ Creatine Phosphokinase structure
Dimeric enzyme; composed of 2 monomer subunits (M or B) M = Muscle and B = Brain
↓ in absorbance at 340 nm is determined; Oxidized NAD
Forward Reaction (Tanzer-Gilvarg)
Forward Reaction (Tanzer-Gilvarg) optimum pH
Optimum pH is 9.0 (alkaline)
Forward Reaction (Tanzer-Gilvarg) primary enzyme
Creatine Kinase
Forward Reaction (Tanzer-Gilvarg) secondary emzymes
Pyruvate Kinase, LDH
↑ in absorbance at 340 nm is determined; Reduced NADPH
Reverse Reaction (Oliver-Rosalki)
Reverse Reaction (Oliver-Rosalki) Optimum pH
Optimum pH: 6.8 (acidic)
Reverse Reaction (Oliver-Rosalki) primary enzyme
Creatine Kinase
Reverse Reaction (Oliver-Rosalki) secondary enzymes
Hexokinase and G-6-PD
Sources of Error
- Hemolysis cause false ↑ CK activity
- CK is inactivated by light (decreased ↓)
- Physical activity and IM injections cause ↑ CK
Creatine Kinase (CK)/ Creatine Phosphokinase Reference Range
Male (higher): 15-160 U/L Female: 15-130 U/L
CK-MB: <6% of total CK
CK-3/ CK-MM/
Muscle Type
Specific to Skeletal Muscle
CK that has lowest mobility toward the anode (least anodic)
CK-3/ CK-MM/ Muscle Type
CK that major isoenzyme in striated muscle and normal serum
CK-3/ CK-MM/ Muscle Type
CK-2/ CK-MB/ Hybrid Type
Specific to the Heart
CK that is 2nd fastest to migrate toward the anode
CK-2/ CK-MB/ Hybrid Type
CK that significant quantities are found in heart tissues
CK-2/ CK-MB/ Hybrid Type
CK-1/ CK-BB Brain Type
Specific to the Brain
CK that migrate fastest toward the anode (most anodic)
CK-1/ CK-BB Brain Type
CK that has Highest conc. in CNS, GI tract, and uterus (pregnancy)
CK-1/ CK-BB Brain Type
In normal serum, CK-BB is ______; negligible
very low
CK-BB increases when there is damage in the ____ → ____
BBB, CSF leakage
The first cardiac enzyme to increase in cases of acute myocardial infarction of all MI markers.
CK-MB (hybrid subunit, specific to the HEART)
The first protein to increase in cases of MI is ______ (faster than CK-MB). The first enzyme however is _______
myoglobin, CK-MB
Has the highest normal value in healthy individuals
CK-MM
CK-MM is predominant in
BLOOD
____________ measurement is not diagnostic because CK is _______
Total CK enzyme, not specific
After MI, CK-MB (>6%) levels begin to rise within ______, peak at _______, and returns to normal levels within ______
4-8 hours, 12-24 hours, 48-72 hours
1st enzyme to increase is __ → ___→ ___
CK → AST → LDH
CK REFERENCE VALUES
CK-MM:
CK-MB:
CK-BB:
CK-MM: 94-98%;
CK-MB: 2-6%;
CK-BB: very low
The CK isoenzyme is coupled/ complexed with antibodies or lipoproteins
Macro-CK
Farthest to ANODE
Mitochondrial CK (CK-Mi)
Migrates cathodal to CK-MM; before CK-3
CK-Mi
Catalyzes the interconversion of lactic and pyruvic acids
Lactate Dehydrogenase (LD)
Lactate Dehydrogenase (LD) IS widely distributed, highest activities in _____, _____, _____ and _____
highest activities in heart, hepatic, skeletal muscle and RBC
LD main source for monomers
Heart & Skeletal Muscle
LD structure
Tetramer with 2 active sub-units (H & M active units) H = HEART and M = MUSCLE
LD second substrate
NAD coenzyme
Forward Reaction (Lactate→Pyruvate)
WACKER METHOD
WACKER METHOD Increase in absorbance is monitored at
340 nm (oxidized → reduced NADH)
WACKER METHOD optimal pH
Optimal pH is 8.3 – 8.9 (basic/ alkaline)
Reverse Reaction (Pyruvate→Lactate)
WROBLEUSKI LA DUE
WROBLEUSKI LA DUE Decrease in absorbance at
Decrease in absorbance at 340 nm
3x faster but more susceptible to substrate exhaustion
WROBLEUSKI LA DUE
WROBLEUSKI LA DUE
optimal pH
Optimal pH is 7.1–7.4
Has greater affinity to H subunits of LDH
α-hydroxybutyrate Dehydrogenase (α-HBD)
After MI, LD begin to:
RISE within ________
PEAK at ________
REMAINS elevated for _______
RISE within 10-24 hours (slowest of all cardiac markers)
PEAK at 48-72 hours or 2-3 days
REMAINS elevated for 10 days (longest to remain elevated)
LD reference range
100-225 U/L
5 LACTATE DEHYDROGENASE (LDH) ISOENZYMES
LDH-1 (HHHH)
LDH-2 (HHHM)
LDH-3 (HHMM)
LDH-4 (HMMM)
LDH-5 (MMMM)
Fastest to migrate LDH isoenzyme, nearest to the anode
LDH-1 (HHHH)
MOST ABUNDANT LDH isoenzyme
LDH-2 (HHHM)
LDH-1 (HHHH) tissues
Heart, RBC (Heart Specific)
LDH-2 (HHHM) tissues
Heart, RBC
LDH-3 (HHMM) tissues
Lung, Spleen
LDH-4 (HMMM) tissues
Liver
LDH-5 (MMMM)
tissue
Skeletal Muscle
LDH-1 (HHHH)
disorder
MI, Hemolytic Anemia (more significant than LD2)
LDH-2 (HHHM)
disorder
Renal Infarction,
Megaloblastic Anemia
LDH-3 (HHMM) disorder
Pulmonary Embolism
LDH-4 (HMMM) disorder
Hepatic Injury
LDH-5 (MMMM)
disorder
Skeletal Muscle Injury
LDH isoenzyme most abundant to least in serum
2>1>3>4>5 (most abundant to least)
LDH isoenzyme Flipped Pattern seen on AMI/ Intravascular Hemolysis
1>2>3>4>5
LDH isoenzyme Muscle & Liver Disorders:
5>4>3>2>1
LD isoenzyme Lung Disorders (LD3):
3>4>2>1>5
CK -MB
Appearance
Peak
Stay Elevated
4-8 hours
12-24 hrs
3 days
AST
Appearance
Peak
Stay Elevated
6-8 hrs
24 hrs
5 days
LDH
Appearance
Peak
Stay Elevated
10-24 hrs
48-72 hrs
10 days
