Sulphur (S) containing amino acids from the following are:
(a) isoleucine
(b) cysteine
(c) lysine
(d) methionine
(e) glutamic acid

Sulphur-containing amino acids have sulphur atoms in their side chains.

(a) Isoleucine: Contains only C, H, O, N in its side chain (branched hydrocarbon). No sulphur. ✗

(b) Cysteine: Contains a thiol (-SH) group in its side chain (HSCH₂-). Contains sulphur. ✓

(c) Lysine: Contains an amino group (-NH₂) in its side chain. No sulphur. ✗

(d) Methionine: Contains a thioether (-S-CH₃) group in its side chain. Contains sulphur. ✓

(e) Glutamic acid: Contains a carboxyl group (-COOH) in its side chain. No sulphur. ✗

The sulphur-containing amino acids are b and d (cysteine and methionine).