91548-83-3Relevant academic research and scientific papers
Diastereospecific, Enzymically Catalysed Transmethylation from S-Methyl-L-methionine to L-Homocysteine, a Naturally Occuring Process
Grue-Soerensen, Gunnar,Kelstrup, Ebbe,Kjaer, Anders,Madsen, Joergen Oegaard
, p. 1091 - 1097 (2007/10/02)
A known catabolic pathway of S-methyl-L-methionine in higher plants: donation of a methyl group to L-homocysteine resulting in the production of two molecules of L-methionine, is subjected to stereochemical studies.The two, diastereoisomeric (2-2H, methyl-13C)-S-methyl-L-methionines are synthesized and utilised in transmethylation reactions with L-homocysteine as the acceptor and an enzyme preparation from jack beans as a catalyst.The resulting, variously labelled methionine species are converted into butyl esters of the N-trifluoroacetylated derivatives and, as such, subjected to g.l.c. combined with mass spectrometry in two ionisation modes.Experimentally determined parameters such as mass peack intensities, isotopic enrichment factors, diastereoisomeric purities, and protein-derived methionine, are utilised for calculating the stereoselectivity in the enzyme transfer of the diastereoisotopic methyl groups from S-methyl-L-methionine to L-homocysteine.Together, the independent results from the two series of diastereoisomers reveal an enzymatic preference of the pro-(R)-methyl group to the extent of 94percent or more.
