Serine hydroxymethyltransferase from Escherichia coli: purification and properties.

摘要: Serine hydroxymethyltransferase from Escherichia coli was purified to homogeneity. The enzyme a homodimer of identical subunits with molecular weight 95,000. amino acid sequence the and carboxy-terminal ends composition cysteine-containing tryptic peptides were in agreement primary structure proposed for this glyA gene (M. Plamann, L. Stauffer, M. Urbanowski, G. Nucleic Acids Res. 11:2065-2074, 1983). contained no disulfide bonds but had one sulfhydryl group on surface protein. Several reagents reacted exposed inactivated enzyme. Spectra presence substrates substrate analogs showed that formed same complexes similar relative concentrations as previously observed cytosolic mitochondrial rabbit liver isoenzymes. Kinetic studies affinity synergistic binding folate those obtained catalyzed cleavage threonine, allothreonine, 3-phenylserine glycine corresponding aldehyde absence tetrahydrofolate. also by D-alanine caused transamination active site pyridoxal phosphate pyridoxamine phosphate. This specificity We conclude reaction mechanism E. serine are very