title: Isolation and properties of 5-aminolevulinate synthase from the yeast Saccharomyces cerevisiae.
abstract: 5-Aminolevulinate synthase from yeast mitochondria has been purified to homogeneity for the first time. By using affinity chromatography on agarose-hexane-CoA, gel filtration and DEAE-Sepharose chromatography, the enzyme was purified about 7000-fold with an overall yield of 40%. The specific activity of the final preparation was 39000 nmol of 5-aminolevulinate h-1 mg-1 of protein at 30 degrees C. As judged by gel filtration, polyacrylamide gradient gel and sodium dodecyl sulfate/polyacrylamide gel electrophoresis, the enzyme appeared to be composed of two identical subunits of a relative molecular mass of 53000. Electrophoresis of sodium-dodecyl-sulfate-solubilized yeast homogenate followed by immune replica analysis showed that the value of 53000 is the Mr of a non-degraded form. The purified enzyme had an isoelectric point of 5.3 and a pH optimum of 7.4. Pyridoxal 5'-phosphate has been shown to be an essential cofactor. The enzyme activity was sensitive to thiol blocking reagents. Hemin, but not heme, inhibited the activity of the purified enzyme.
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000302:isolation & purification* / Q000378:metabolism; D002451:Cell Compartmentation; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances; D008928:Mitochondria / Q000201:enzymology; D008970:Molecular Weight; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
chemical_list: D046911:Macromolecular Substances; D000624:5-Aminolevulinate Synthetase