Enzymes and Cardiac Assessment

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Enzymes and Cardiac Assessment
2013-05-04 20:58:23
Cardiac Profile Natiuretic Peptides High Sensitivity CRP Homocysteine General Properties

Cardiac Profile, Natiuretic Peptides, High-Sensitivity CRP, and Homocysteine, General Properties
Show Answers:

  1. 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
  2. What is used as an AMI indicator because of specificity and early rise in serum concentration following an AMI?
    Troponin (cTnT or cTnI)
  3. 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
  4. What is the reference range of troponin?
    • cTnT: <0.03 ng/mL
    • cTnI: <0.4 ng/mL
  5. Where is myoglobin found?
    • Skeletal muscle
    • Cardiac muscle
  6. 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
  7. What is the reference range of myoglobin?
    • Male: 30-90 ng/mL
    • Female: <50 ng/mL
  8. What are the 3 forms of the Natiuretic Peptides (polypeptide hormones)?
    • ANP
    • BNP
    • CNP
  9. What functions to promote excretion of sodium and water by increasing glomerular filtration rate and decreasing the tubular reabsorption of Na by the kidneys
    • ANP
    • BNP
    • CNP
  10. What is synthesized in and secreted from myocardial ventricles in response to ventricular volume expansion and pressure overload?
  11. What causes an increase in BNP?
    Congestive heart failure (CHF)
  12. What is the reference range of BNP
    <100 pg/mL
  13. What clinical conditions are associated with CRP?
    • Predictor for cardiovascular risk
    • Inflammation
    • Infection
    • Stress
    • Trauma
    • AMI
  14. What is the reference range of hs-CRP?
    • Males: 0.3-8.6 mg/L
    • Females: 0.2-9.1 mg/L
  15. 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
  16. What causes an increase of homocysteine?
    • Elevated levels cause damage to arterial walls that precedes formation of plaques
    • Indicator of arterial inflammation
  17. What is the reference range of homocysteine?
    5-15 micro-mol/L
  18. What test methodology is used to measure homocysteine?
    • Immunoassay
    • Fluorometric
    • Chromatographic
  19. What are proteins that function as biological catalysts and are neither consumed nor permanently altered during a chemical reaction?
  20. What appears in the serum in increased amounts after cellular injury or tissue damage?
  21. What are different forms of the same enzyme that are capable of the same catalytic function in the body?
  22. How are Isoenzymes differentiated?
    Based on eletrophoretic mobility and resistance to heat denaturation
  23. What a nonprotein compound that may be required for enzyme activity?
  24. What are inorganic cofactors needed for enzymatic activity, such as Mg2+, Zn2+, or Cl-?
  25. What are organic cofactors, such as NAD+ (nicotinamide adenine dinucleotide)?
  26. What are organic cofactors that are tightly bound to the enzyme?
    Prosthetic group
  27. What is the location on an enzyme where the 3-D arrangement of amino acid residues allows binding of substrate?
    Active site
  28. 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?
  29. 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
  30. What increases the rate of chemical reactions by lowering the activation energy required by substrate to react and form the product?
  31. What binds to free enzyme at low substrate concentrations?
  32. What is the term for the rate of the reaction is directly proportional to substrate concentration?
    First-order kinetics
  33. For substrate, when is the reaction velocity at its maximum?
    When the substrate concentration is high enough to bind with all available enzymes
  34. The reaction velocity is proportional to the ____________
    Enzyme concentration
  35. 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?
  36. At what pH do most enzymes of physiological interest function at?
  37. An increase of ___________ will increase the rate of a chemical reaction
  38. What is the optimal temperature for enzymes?
    37 degrees celcius
  39. At what temperature do enzymes generally denature?
    40-50 degrees celcius
  40. What is a substance that interferes with an enzyme-catalyzed reaction?
  41. What competes with a substrate for the active site (which is reversible)?
    Competitive inhibitor
  42. What binds with the enzyme at a site different from the active site and prevents the enzyme-catalyzed reaction from taking place?
    Noncompetitive inhibitor
  43. 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