The aconitase of yeast. IV. Studies on iron and sulfur in yeast aconitase.
Chemical analyses were carried out to determine the active components of the crystalline aconitase [EC 4.2.1.3] of Candida lipolytica. The enzyme contained 2 atoms of non-heme iron, 1 atom of labile sulfur, and 6 sulfhydryl groups per molecule. One atom of the non-heme iron was released by the addition of metal-chelating agents such as sodium citrate, sodium nitrilotriacetate (NTA) or sodium ethylenediaminetetraacetate (EDTA) without loss of the enzyme activity. The non-heme iron and labile sulfur were released by the addition of sulfhydryl reagents such as rho-chloromercuribenzoate (PCMB), sodium mersalyl or urea with loss of the enzyme activity. o-Phenanthroline reacted with the iron atoms in the enzyme at pH 6.0 with loss of the activity. These results show that yeast aconitase is an iron-sulfur protein and that only one of the two non-heme iron atoms is essential for enzyme activity.
D000154:Aconitate Hydratase; D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D002175:Candida / Q000201:enzymology*; D002614:Chelating Agents; D002729:Chloromercuribenzoates; D006836:Hydro-Lyases; D007501:Iron / Q000032:analysis; D007700:Kinetics; D010618:Phenanthrolines; D011485:Protein Binding; D011487:Protein Conformation; D013053:Spectrophotometry; D013438:Sulfhydryl Compounds / Q000032:analysis; D013439:Sulfhydryl Reagents; D013455:Sulfur / Q000032:analysis
D000596:Amino Acids; D002614:Chelating Agents; D002729:Chloromercuribenzoates; D010618:Phenanthrolines; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D013455:Sulfur; D007501:Iron; D006836:Hydro-Lyases; D000154:Aconitate Hydratase