Table 1.

Basic structure of sulfur-containing groups and their occurrence (data from Raab and Feldmann, 2019) [45].

Sulfur-containing compounds	Present in
HS–CH2–R	cystine
H3C–S–CH2–R	methionine
R–S–S–R	disulfide (e.g. cystine, a relative of allin)
HOS–R	sulfenic acid (post-translational modification of cysteine in proteins)
HO2S–R	sulfinic acid (the modification of cysteine in proteins)
HO3–S–CH2–R	in fat
HO3–S–O–CH2–R	in fat