91Ó°ÊÓ

Draw the structure of adenosine 5’-monophosphate (AMP), an intermediate in some biochemical pathways.

Cyclic adenosine monophosphate (cyclic AMP), a modulator of hormone action, is related to AMP (Problem 29-35) but has its phosphate group linked to two hydroxyl groups at C3’ and C5’ of the sugar. Draw the structure of cyclic AMP.

What general kind of reaction does ATP carry out?

What general kind of reaction does NAD⁺ carry out?

What general kind of reaction does FAD carry out?

PROBLEM 29-3How many molecules of acetyl $\mathbf{CoA}$are produced by catabolism of the following fatty acids, and how many passages of the $\mathbf{β}\mathbf{-}$oxidation pathway are needed?

(a) Palmitic acid,localid="1663327972127" ${\mathbf{CH}}_{\mathbf{3}}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}}_{\mathbf{14}}{\mathbf{CO}}_{\mathbf{2}}\mathbf{H}$.

(b) Arachidic acid,${\mathbf{CH}}_{\mathbf{3}}{\mathbf{\left(}{\mathbf{CH}}_{\mathbf{2}}\mathbf{\right)}}_{\mathbf{18}}{\mathbf{CO}}_{\mathbf{2}}\mathbf{H}$.

What enzyme cofactor is associated with each of the following kinds of reactions?

(a) Transamination

(b) Carboxylation of a ketone

(c) Decarboxylation of an $\mathit{Î\pm }\mathbf{-}\mathbf{\text{ketoacid}}$

Lactate, a product of glucose catabolism in oxygen-starved muscles, can be converted into pyruvate by oxidation. What coenzyme do you think is needed? Write the equation in the normal biochemical format using a curved arrow.

Why aren’t the glycolysis and gluconeogenesis pathways the exact reverse of each other?

PROBLEM 29-4Write a mechanism for the dehydration reaction of $\mathbf{β}\mathbf{-}$hydroxybutyryl ACP to yield crotonyl ACP in step 7 of fatty-acid synthesis.