Enzymes Flashcards
CK isoenzyme found in highest concentration in the blood
CK-MM
Type of inhibition wherein the inhibitor attaches itself to the active site of the enzyme
Competitive
Inactive enzymes are termed as ___, which are common among digestive enzymes
Proenzymes
Most electronegative LD isoenzyme
LD1
What are the conditions for zero-order kinetics?
Substrate concentration is higher than enzyme concentration
Which LD isoenzyme appears indicative of arteriosclerotic cardiovascular failure?
LD6
This enzyme functions is maintain NADPH in a reduced form which is responsible for regenerating sulfhydryl-containing proteins (ie glutathione) from oxidized to reduced state
Glucose-6-phosphate dehydrogenase
The slowest moving fraction of CK is typically elevated in patients with:
Skeletal muscle disorders
Hemolyzed serum cannot be used for AST determination because:
Erythrocytes contain a large amount of AST
Correct arrangement of the classes of enzymes
Oxidoreductase, transferase, hydrolase, lyase, isomerase, ligase
Indicator enzyme used in Karmen method
Malate dehydrogenase
Chemical inhibition of ALP using Phenylalanine
Inhibits 75% of intestinal and 80% of placental ALP
Which enzyme is most useful in identifying the source of ALP elevation?
GGT
An amylase method which measures the disappearance of the starch substrate
Amyloclastic
What results when an enzyme is subject to post-translational modifications?
Isoform
Also known as organic cofactors
Coenzymes
What are the classes of enzymes?
Oxidoreductases Transferases Hydrolases Lyases Isomerases Ligases
In the Michaelis-Menten curve, Km is defined as the:
Substrate concentration at which v is half of Vmax
The Km of an enzyme reaction is ____ proportional to the affinity of a substrate to its enzyme.
Inversely
In this type of inhibition, increasing substrate concentration further increases inhibition.
Uncompetitive inhibition
1 IU can be defined as:
Amount of enzyme that will catalyze the reaction of 1 umol of substrate in 1 minute
1 Katal can be defined as:
Amount of enzyme that will catalyze the reaction of 1 mole of substrate in 1 second
1 IU = ___ kat
17
These conditions cause a pronounced elevation (>5x) in CK measurement.
DMD
Polymyositis
Dermatomyositis
Myocardial infarction