High Quality Content by WIKIPEDIA articles! In molecular biology, the CBS domain is a protein domain found in a range of proteins in all species from bacteria to man. It was first identified as a conserved sequence region in 1997 and named after cystathionine beta synthase, one of the proteins it is found in. CBS domains are also found in a wide variety of other proteins such as inosine monophosphate dehydrogenase,voltage gated chloride channels and AMP-activated protein kinase (AMPK). CBS domains regulate the activity of associated enzymatic and transporter domains in response to binding molecules with adenosyl groups such as AMP and ATP, or s-adenosylmethionine.