Table 2.

Terms Defined for This Standard

term	definition
descriptor	Member of the tag. Could be a key-value pair or a keyless entry.
human readable	A strong emphasis is placed on human readability for proteoform names. Proteoforms should be named in a manner that allows general audience members to know exactly the sequence of amino acids and the positions of any modifications, described in as accurate detail as possible.
key	An optional element of a descriptor that specifies the descriptor type. It must be followed by a colon and a value.
machine readable	Adherence to the conventions described above should facilitate the creation and utilization of generic parsers so that proteoforms can be exchanged between users using a computer interface.
modification	Includes the addition and subtraction of specific atoms, atom combinations, and/or masses at a specific residue in a proteoform.
tag	The specified way of writing a localized modification. Everything between “[” and “]” (inclusive). A collection of descriptors.
value	Contents of a descriptor, such as the mass, chemical composition, or modification name.