Possible role of isoaspartyl methyltransferase towards regulation of acid trehalase activity in Saccharomyces cerevisiae.
Logarithmically growing cells of S. cerevisiae contained high neutral trehalase (NT) activity while stationary-phase cells had high acid trehalase (AT) activity. Change in activity profile of AT and NT were different during growth under different conditions, particularly during growth in acetate medium and up to 1 h of germination period, but that for AT and isoaspartyl methyltransferase (IMT) were found to be almost identical. Concomitant increase in NT activity as well as increase in cAMP level was noticed at the onset of spore germination. Increase in AT and IMT activities as well as decrease in S-adenosyl-L-methionine (AdoMet) level were noticed during stationary phase of growth. Acidic polyacrylamide gel electrophoresis and subsequent autoradiography revealed that substrate of IMT was a protein of molar mass around 82 kDa which could be an AT. Methylated AT was found to be more active while non-methylated AT was relatively less active in comparison to the untreated sample. Since AT existed as an equilibrium mixture of protomer and oligomer, it was suggested that IMT catalysed carboxyl methylation might have some contribution towards the regulation of AT activity.
Biswas
N
N
Applied Biochemistry Department, Indian Institute of Chemical Biology, Calcutta.
Ghosh
A K
AK
D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D005656:Fungal Proteins / Q000378:metabolism*; D008745:Methylation; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase; D011496:Protein Methyltransferases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D014198:Trehalase / Q000378:metabolism*
D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D011496:Protein Methyltransferases; D026601:Protein D-Aspartate-L-Isoaspartate Methyltransferase; C097090:ATH1 protein, S cerevisiae; D014198:Trehalase