What is the definition of “amino acid” according to MPEP 2412.03(b)?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

According to MPEP 2412.03(b), the definition of “amino acid” is broad and inclusive. The section states:

“‘Amino acid’ includes any D- or L-amino acid or modified amino acid as defined in paragraph 3(a) of WIPO Standard ST.26.”

This definition encompasses not only standard L-amino acids but also D-amino acids and modified amino acids with synthetic side chains. It’s important to note that peptide nucleic acid (PNA) residues are considered nucleotides, not amino acids.