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The troponins T, I, and C form a complex of 3 proteins that bind to what?
Bind to filaments of skeletal muscle and cardiac muscle to regulate muscle contraction
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What is used as an AMI indicator because of specificity and early rise in serum concentration following an AMI?
Troponin (cTnT or cTnI)
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When does troponin increase after AMI?
- cTnT increases 3-4 hrs, peaks 10-24 hrs, and returns to normal 10-14 days
- cTnI increases 3-6 hrs, peaks 14-20 hrs, and returns to normal 5-10 days
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What is the reference range of troponin?
- cTnT: <0.03 ng/mL
- cTnI: <0.4 ng/mL
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Where is myoglobin found?
- Skeletal muscle
- Cardiac muscle
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What causes an increase in myoglobin?
- Skeletal muscle injuries
- Muscular dystrophy
- AMI
- Released in early cases of AMI (rising 1-3 hrs) - not specific, so it is better as a negative predictor
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What is the reference range of myoglobin?
- Male: 30-90 ng/mL
- Female: <50 ng/mL
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What are the 3 forms of the Natiuretic Peptides (polypeptide hormones)?
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What functions to promote excretion of sodium and water by increasing glomerular filtration rate and decreasing the tubular reabsorption of Na by the kidneys
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What is synthesized in and secreted from myocardial ventricles in response to ventricular volume expansion and pressure overload?
BNP
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What causes an increase in BNP?
Congestive heart failure (CHF)
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What is the reference range of BNP
<100 pg/mL
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What clinical conditions are associated with CRP?
- Predictor for cardiovascular risk
- Inflammation
- Infection
- Stress
- Trauma
- AMI
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What is the reference range of hs-CRP?
- Males: 0.3-8.6 mg/L
- Females: 0.2-9.1 mg/L
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What is the cardiovascular risk classification for hs-CRP?
- Low risk: <1.0 mg/L
- Average risk: 1.0-3.0 mg/L
- High risk: >3.0 mg/L
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What causes an increase of homocysteine?
- Elevated levels cause damage to arterial walls that precedes formation of plaques
- Indicator of arterial inflammation
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What is the reference range of homocysteine?
5-15 micro-mol/L
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What test methodology is used to measure homocysteine?
- Immunoassay
- Fluorometric
- Chromatographic
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What are proteins that function as biological catalysts and are neither consumed nor permanently altered during a chemical reaction?
Enzymes
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What appears in the serum in increased amounts after cellular injury or tissue damage?
Enzymes
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What are different forms of the same enzyme that are capable of the same catalytic function in the body?
Isoenzymes
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How are Isoenzymes differentiated?
Based on eletrophoretic mobility and resistance to heat denaturation
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What a nonprotein compound that may be required for enzyme activity?
Cofactor
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What are inorganic cofactors needed for enzymatic activity, such as Mg2+, Zn2+, or Cl-?
Activators
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What are organic cofactors, such as NAD+ (nicotinamide adenine dinucleotide)?
Coenzyme
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What are organic cofactors that are tightly bound to the enzyme?
Prosthetic group
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What is the location on an enzyme where the 3-D arrangement of amino acid residues allows binding of substrate?
Active site
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What causes change in enzyme structure that results in loss of activity; which may be caused by elevated temp, extreme change in pH, and certain chemicals?
Denaturation
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What is the energy required to raise all molecules to the transition state in a chemical reaction so that products may be formed?
Activation energy
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What increases the rate of chemical reactions by lowering the activation energy required by substrate to react and form the product?
Enzymes
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What binds to free enzyme at low substrate concentrations?
Substrate
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What is the term for the rate of the reaction is directly proportional to substrate concentration?
First-order kinetics
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For substrate, when is the reaction velocity at its maximum?
When the substrate concentration is high enough to bind with all available enzymes
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The reaction velocity is proportional to the ____________
Enzyme concentration
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What is an important factor to be controlled because it can denature an enzyme or change its ionic state and possibly the reactivity of the active site?
pH
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At what pH do most enzymes of physiological interest function at?
7.0-8.0
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An increase of ___________ will increase the rate of a chemical reaction
temperature
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What is the optimal temperature for enzymes?
37 degrees celcius
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At what temperature do enzymes generally denature?
40-50 degrees celcius
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What is a substance that interferes with an enzyme-catalyzed reaction?
Inhibitors
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What competes with a substrate for the active site (which is reversible)?
Competitive inhibitor
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What binds with the enzyme at a site different from the active site and prevents the enzyme-catalyzed reaction from taking place?
Noncompetitive inhibitor
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What binds to the enzyme-substrate complex so that increasing the concentration of substrate leads to the formation of more enzyme-substrate complexes and more inhibition?
Uncompetitive inhibitor
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