NH3CHRCOO
NH3CHRCOO is a shorthand chemical representation used to depict the zwitterionic form of an amino acid. In this schematic, the amino group is protonated (often written as NH3+) and the carboxyl group is deprotonated (COO−), attached to a central alpha carbon that bears a side chain denoted by R. The R group can be any of the standard amino acid side chains, such as hydrogen (glycine), methyl (alanine), or more complex substituents.
In solution, amino acids typically exist as zwitterions at physiologic pH. The common form is NH3+-CHR-COO−, reflecting
The zwitterionic form is central to amino acid chemistry, influencing solubility, reactivity, and interactions in proteins.