Lecture Podcast 3

Question 1

Statins competitively inhibit ____-CoA reductase.

Answer 1

HMG-CoA reductase

Question 2

As part of HAART therapy for HIV, nucleoside and nucleotide analogs act as _____ inhibitors while non-nucleoside analogs act as ______ inhibitors on ______ trancriptase.

Answer 2

Competitive

Non-competitive

Reverse transcriptase

Question 3

_____ enzymes show a sigmoidal curve (which dissociation curve does this remind you of?) on a Michaelis-Menten plot. These enzymes have at least 2 different binding sites on their surface, where the substrate can bind one and an _____ can bind another to alter the enzyme’s activity. If the _____ is the same as the substrate, it’s called _____, and has mostly positive effects on rxn velocity; if it’s different, it’s called _____ and has mostly negative effects on rxn velocity.

Answer 3

Allosteric

Effector

Effector

Homotropic

Heterotropic

Question 4

For feedback by heterotropic factors, typically the first _____ step UNIQUE to the pathway is inhibited.

Answer 4

Irreversible

Question 5

______ is the term for enzymes that have the same function, but are expressed with slight variations that are tissue specific. These are good diagnostic targets. For example, _____ kinase has different forms expressed in the heart vs skeletal muscle vs the brain. In the heart, it is of the form ____-____. These different forms have different ______ properties, which is useful in separating them on a gel. However, _____ is a better diagnostic isozyme for myocardial infarction.

Answer 5

Isozymes

Creatine Kinase (or creatine phosphokinase)

CK-MB

Electrophoretic

cTnI