Metabolism of Cysteine & Methionine and Related Inborn Errors (Homocystinuria & Homocysteinemia): Biochemistry
Metabolic Pathway of Methionine and Cysteine Conversion of Methionine to S-Adenosyl Methionine - Methionine is a nutritionally essential amino acid, therefore, the dietary source is generally proteins. - S-adenosyl methionine synthase catalyzes the conversion of methionine to S-adenosyl methionine - Require ATP, the ATP is hydrolyzed to AMP and PPi, therefore two energy equivalent of ATP is consumed in the reaction Figure 1: Metabolic Pathway for the methionine metabolism Formation of S-Adenosyl homocysteine from S-Adenosyl methionine - S-adenosyl methionine serves as an active methyl group donor in various metabolic pathways including amino acid metabolism, hormones/neurotransmitter synthesis, etc. - Once the methyl group is transferred to the methyl acceptor, the S-Adenosyl methionine is formed - Generally transferred by specific methyltransferase Hydrolysis of S-Adenosyl homocysteine to form homocysteine -The hydrolysis of S-Adenosyl homocysteine form...