Distribution and Properties of Thiol S‐Methyltransferase in Rat Brain

Abstract

Microsomal thiol S-methyltransferase (TMT) of rat brain catalysed the methylation of dithiothreitol (Km = 84 microM) and other thiol compounds using S-adenosylmethionine as methyl donor (Km = 3.7 microM). With increasing polarity of thiol substrates there was a decrease in the maximal velocities of reaction and an increase in the apparent Km values. TMT was found to be unevenly distributed amongst various brain regions, with highest activities in the medulla oblongata and the hippocampus.

METTL7A and METTL7B are responsible for S -thiol methyl transferase activity in liver

“…Potential TMT substrates were screened at concentrations at least three times higher than their literature reported Km values to ensure the detection of methylation activity (Weisiger and Jakoby, 1979; Rivett and Roth, 1982; Drummer et al, 1983; Hiemke and Ghraf, 1983; Keith et al, 1984; Keith et al, 1985; Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”

METTL7A and METTL7B are responsible for S -thiol methyl transferase activity in liver

“…Potential TMT substrates were screened at concentrations at least three times higher than their literature reported Km values to ensure the detection of methylation activity (Weisiger and Jakoby, 1979; Rivett and Roth, 1982; Drummer et al, 1983; Hiemke and Ghraf, 1983; Keith et al, 1984; Keith et al, 1985; Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”

METTL7A (TMT1A) and METTL7B (TMT1B) Are Responsible for Alkyl S-Thiol Methyl Transferase Activity in Liver

“…Potential substrates were screened at concentrations at least three times higher than their literature reported K m values to ensure the detection of methylated metabolites (Weisiger and Jakoby, 1979;Rivett and Roth, 1982;Drummer et al, 1983;Hiemke and Ghraf, 1983;Keith et al, 1984;Keith et al, 1985;Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”

METTL7A and METTL7B are responsible for S -thiol methyl transferase activity in liver

“…Potential TMT substrates were screened at concentrations at least three times higher than their literature reported Km values to ensure the detection of methylation activity (Weisiger and Jakoby, 1979; Rivett and Roth, 1982; Drummer et al, 1983; Hiemke and Ghraf, 1983; Keith et al, 1984; Keith et al, 1985; Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”

METTL7A (TMT1A) and METTL7B (TMT1B) Are Responsible for Alkyl S-Thiol Methyl Transferase Activity in Liver

“…Potential substrates were screened at concentrations at least three times higher than their literature reported K m values to ensure the detection of methylated metabolites (Weisiger and Jakoby, 1979;Rivett and Roth, 1982;Drummer et al, 1983;Hiemke and Ghraf, 1983;Keith et al, 1984;Keith et al, 1985;Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”

METTL7A and METTL7B are responsible for S -thiol methyl transferase activity in liver

“…Potential TMT substrates were screened at concentrations at least three times higher than their literature reported Km values to ensure the detection of methylation activity (Weisiger and Jakoby, 1979; Rivett and Roth, 1982; Drummer et al, 1983; Hiemke and Ghraf, 1983; Keith et al, 1984; Keith et al, 1985; Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”

METTL7A (TMT1A) and METTL7B (TMT1B) Are Responsible for Alkyl S-Thiol Methyl Transferase Activity in Liver

“…Potential substrates were screened at concentrations at least three times higher than their literature reported K m values to ensure the detection of methylated metabolites (Weisiger and Jakoby, 1979;Rivett and Roth, 1982;Drummer et al, 1983;Hiemke and Ghraf, 1983;Keith et al, 1984;Keith et al, 1985;Grunewald et al, 1989). METTL7A preferentially methylated exogenous thiol-containing compounds and did not methylate the endogenous thiols tested; cysteine and glutathione (Fig.…”