Disease relevance of MTR

• The presence of a previously unidentified enzyme, tentatively designated 5-methylthioribose kinase, has been demonstrated in cell-free extracts of Enterobacter aerogenes [1].
• Selective killing of Klebsiella pneumoniae by 5-trifluoromethylthioribose. Chemotherapeutic exploitation of the enzyme 5-methylthioribose kinase [2].
• Streptococcus pneumoniae 5'-methylthioadenosine/S-adenosylhomocysteine hydrolase (MTAN) catalyzes the hydrolytic deadenylation of its substrates to form adenine and 5-methylthioribose or S-ribosylhomocysteine (SRH) [3].
• Trivalent holmium ions were shown to isomorphously replace magnesium ions to form an ADP-2Ho complex in the nucleotide-binding domain of Bacillus subtilis 5-methylthioribose (MTR) kinase [4].
• Escherichia coli can not synthesize methionine from 5-methylthioribose (MTR) but instead exports this sulfur-containing, energy-rich molecule into the surrounding medium [5].

High impact information on MTR

• The enzyme catalyzes the ATP-dependent phosphorylation of 5-methylthioribose [1].
• The substrate specificity of the enzyme is quite narrow, and the Km values for ATP and 5-methylthioribose are 7.4 X 10(-5) M and 8.1 X 10(-6) M, respectively [1].
• Like L-methionine and vitamin B12, 5'-methylthioadenosine and 5-methylthioribose may play an important role in maintenance of the C-1 pool in Ochromonas malhamensis [6].
• In vivo hydrolysis of S-adenosyl-L-methionine in Escherichia coli increases export of 5-methylthioribose [5].
• The first step on the salvage pathway of the methylthio group is, in Aspergillus nidulans, phosphorolytic cleavage of 5'-methylthioadenosine to adenine and 5-methylthioribose 1-phosphate catalyzed by a specific phosphorylase [7].

References