title: 5-methylthioribose 1-phosphate: a product of partially purified, rat liver 5'-methylthioadenosine phosphorylase activity.
abstract: 5'-Methylthioadenosine phosphorylase from rat liver has been purified 112-fold. A molecular weight of 90 000 for the enzyme was estimated from gel filtration on Sephadex G-150. The Km for 5'-methylthioadenosine was 4.7 . 10(-7) M, while the Km for phosphate was 2 . 10(-4) M. The products of the reaction were isolated and identified as adenine and 5-methylthioribose 1-phosphate. In addition to 5'-methylthioadenosine the nucleoside analogues 5'-ethylthioadenosine and 5'-n-propylthioadenosine also served as substrates for the enzyme. The 7-deaza analogue 5'-methylthiotubercidin was found to be an inhibitor of the reaction, but was inactive as a substrate.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives; D000818:Animals; D005260:Female; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D010430:Pentosyltransferases / Q000378:metabolism*; D011683:Purine-Nucleoside Phosphorylase / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D012436:S-Adenosylmethionine / Q000378:metabolism*; D013379:Substrate Specificity; D013865:Thioglycosides / Q000378:metabolism; D013872:Thionucleosides / Q000378:metabolism; D014372:Tubercidin / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D013865:Thioglycosides; D013872:Thionucleosides; C021716:5'-methylthiotubercidin; D012436:S-Adenosylmethionine; D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; C021784:5'-methylthioadenosine phosphorylase; D000241:Adenosine; D014372:Tubercidin