Acetyl group known as paracetamol), and acetylsalicylic acid (better known as aspirin). The introduction of an acetyl group into a molecule is called acetylation. In biological organisms, acetyl groups are commonly transferred from acetyl-CoA to other organic molecules. Acetyl-CoA is an intermediate both in the biological synthesis and in the breakdown of many organic molecules. Acetyl-CoA is also created during the second stage of cellular respiration, the Krebs Cycle, by the action of pyruvate dehydrogenase on pyruvic acid. Histones and other proteins are often modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases (HATs) causes an expansion of
Cob(I)yrinic acid a,c-diamide adenosyltransferase as: Cob(I)yrinic acid a,c-diamide adenosyltransferase In molecular biology, cob(I)yrinic acid a,c-diamide adenosyltransferase (also known as ATP:cob(I)alamin adenosyltransferase or ATP:corrinoid adenosyltransferase) is an enzyme which catalyses the conversion of cobalamin (vitamin B12) into one of its coenzyme forms, adenosylcobalamin (coenzyme B12, AdoCbl). Adenosylcobalamin is required as a cofactor for the activity of certain enzymes. AdoCbl contains an adenosyl moiety liganded to the cobalt ion of cobalamin via a covalent Co-C bond. ATP:cob(I)alamin adenosyltransferases are classed into three groups: CobA-type, EutT-type and PduO-type. Each of the three enzyme types appears to be specialised for particular AdoCbl-dependent enzymes or for the de novo