Guanidine special group is presesnt in
AMINO ACID SPECIAL GROUP Arginine Guanidinium Proline Pyrolidine Tryptophan Indole Phenylalanine Benzene Tyrosine Phenol Histidine Imidazole Methionine Thioether linkage Reference: Harpers illustrated biochemistry 30th edition
Arginine
Proline
Tryptophan
Tyrosine
General anatomy