Identify a side chain $(R)$ group present in Leucine, an amino acid.

Identify a side chain $(R)$ group present in Leucine, an amino acid.
  1. $\mathrm{H}-$
  2. $-\mathrm{CH}_3$
  3. $\mathrm{Me}_2 \mathrm{CH}-$
  4. $\mathrm{Me}_2 \mathrm{CH}-\mathrm{CH}_2-$

Solution

The side chain (R group) of leucine is an isobutyl group with structural formula $\mathrm{Me}_2\mathrm{CH}-\mathrm{CH}_2-$.

Comparing the options:
A) $\mathrm{H}-$ (glycine)
B) $-\mathrm{CH}_3$ (alanine)
C) $\mathrm{Me}_2\mathrm{CH}-$ (valine)
D) $\mathrm{Me}_2\mathrm{CH}-\mathrm{CH}_2-$ (leucine)

The isobutyl group corresponds to option D.

Asked in: MHT CET 2025 (05 May Shift 2)

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