Question

Consider the first reaction of $TCA$ cycle.

What is true about compound $A$?

• A. First product of $TCA$ cycle
• B. Tricarboxylic acid and six carbon compound
• C. It undergoes reorganisation in the presence of enzyme aconitase to form cis-aconitate
• D. All of these

Answer 1

Answer: (D)

The $TCA$ cycle starts with the condensation of acetyl group with oxaloacetic acid and water to yield citric acid. It is a tricarboxylic $6$-carbon compound and undergoes reorganisation in the presence of iron containing enzyme aconitase first forming cis aconitate and releasing water.
Citrate $\underset{F{e}^{+2}}{\overset{\text{Aconitase}}{\to }}$ $cis$ - aconitate $+H_{2}O$