SAdenosylmethionine

To consider S-adenosylmethionine (SAM, also known as adomet) a cofactor is to recognize its role in a multitude of reactions that transfer methyl groups to substrates. Thus, SAM is involved in an extensive series of methylation reactions that surpass methylations of either N5-methyl-FH4 or methyl cobalamin combined. The methyl group transferred is the terminal carbon of methionine. To activate the methyl group, methionine reacts with ATP, adding an adenosyl group to the sulfur atom and causing a high-energy methyl-donating species to form (Figure 14). Although SAM is perhaps more of a substrate than a cofactor, its inclusion here is to denote the importance of methionine and its reactive

COO-I

COO-I

H3N-C-H

H3N-C-H

-CH2

HO OH

L-Methionine S-Adenosylmethionine

Figure 14 Synthesis of S-adenosylmethionine from methionine. Note the favorable positioning of the methyl group of methionine (dotted circle) as a result of the condensation with ATP.

form, SAM, in a series of extremely important biosynthetic reactions.

Was this article helpful?

0 0
Quick Weight Loss Action

Quick Weight Loss Action

Why Indulge In Self-Pity When You Can Do Something About Your Weight Now. Say Goodbye to Your Weight Problems That Have Only Make Your Life Nothing But Miserable. Have you often felt short-changed because of your weight or physical appearance?

Get My Free Ebook


Post a comment