UNE Biochem week 1 quiz with well
explained test.
An enzyme has a mutation within the substrate binding site that reduces the binding of
the coenzyme needed for covalent catalysis. Which of the following is likely to result as
a consequence of this mutation? - correct answers.the enzyme will not be able to form
the transition state complex
Covalent catalysis is used by many enzymes to cleave peptide bonds. Which of the
following amino acids would not facilitate this type of catalysis? (Think of the structure of
the R-group of these amino acids) - correct answers.Valine
The R-group on valine does not have an active group to participate in covalent
catalysis. The most commonly participating amino acids are cysteine, serine and
histidine.
A 55-year old man is brought to the emergency room with a chief complaint of chest
pain and tingling in his left arm. Elevation of which of the following enzymes in
circulation would be most indicative of a myocardial infarction? - correct
answers.Troponin
MI is diagnosed by elevation of troponin, cardiac specific troponins would be the most
accurate answer for this diagnosis. Amylase and lipase would indicate pancreatitis;
elevation of lactate dehydrogenase is non-specific for muscle damage. Although LDH
may be elevated, in the case of an MI it would not be a definitive indicator.
Prosthetic groups are complex nonprotein molecules that participate in catalysis by
providing functional groups that form a covalent intermediate between the enzyme and
the substrate. Which of the following is an example of a coenzyme or cofactor that
participates in a covalent catalysis reaction? - correct answers.Pyridoxal phosphate
Amino transferases are commonly used in the movement of ammonia and use the
covalent catalysis "ping-pong method". NADH and FAD are commonly used in oxidation
reduction reactions and ATP is typically an energy carrier within an reaction.
