title: The S-n-propyl analogue of S-adenosylmethionine.
abstract: A special strain of Saccharomyces cerevisiae responded to a supplement of S-n-propyl-L-homocysteine in the culture medium by synthesizing S-adenosyl-(S-n-propyl)L-homocysteine, the S-n-propyl analogue of S-adenosylmethionine. S-n-Butyl-L-homocysteine reacted sparingly with this strain, but S-isopropyl-L-homocysteine failed to form detectable quantities of the corresponding S-adenosylsulfonium compound. The S-n-propyl compound was isolated by extraction of the cells, followed by ion-exchange chromatography, which separated it from endogenous S-adenosylmethionine. The structure was determined by hydrolytic procedures leading to overlapping fragments of known structure, 5'-n-propylthioadenosine and S-n-propyl-L-homocysteine. The new sulfonium compound was examined for its activity as n-propyl donor by substituting it for S-adenosylmethionine in methyltransferase systems. Enzymatic transpropylation was observed with S-adenosylmethionine : L-homocysteine S-methyltransferase (EC 2.1.1.10). Its rate was low in the S-adenosylmethionine : N-acetylserotonin O-methyltransferase system (EC 2.1.1.4), and below recognition with S-adenosylmethionine : guanidinoacetate methyltransferase (EC 2.1.1.2) and S-adenosylmethionine : histamine N-methyltransferase (EC 2.1.1.8).
mesh_terms: D000085:Acetates; D000241:Adenosine; D006146:Guanidines; D006632:Histamine; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000302:isolation & purification; D008780:Methyltransferases / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000031:analogs & derivatives*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D012701:Serotonin; D013329:Structure-Activity Relationship; D013440:Sulfides / Q000378:metabolism
chemical_list: D000085:Acetates; D006146:Guanidines; D013440:Sulfides; D006710:Homocysteine; D012701:Serotonin; D012436:S-Adenosylmethionine; D006632:Histamine; D008780:Methyltransferases; D000241:Adenosine