Purification and characterization of chicken erythrocyte ferrochelatase.
Ferrochelatase (EC 4.99.1.1) was purified 2000-fold to apparent homogeneity from isolated chicken erythrocyte mitochondria. The purified enzyme yields a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with an apparent Mr of 42 000. The enzyme utilizes proto-, meso- and deutero-porphyrin with Km values of 37, 51 and 80 microM respectively. The disubstituted porphyrins 2,4-bisglycol deutero-porphyrin and 2,4-disulphonic deuteroporphyrin were not substrates. Mn2+, Hg2+, Pb2+ and Co2+ were strong inhibitors of the purified enzyme. Palmitic acid and oleic acid stimulated activity, whereas linoleic acid inhibited and phospholipids had variable effects. Chicken ferrochelatase was inhibited by N-ethylmaleimide and iodoacetamide. Inhibition by iodoacetamide was pseudo-first-order, but inhibition by N-ethylmaleimide appeared to be biphasic in nature with an initial high rate followed by a much lower rate of inactivation. The characteristics of the chicken erythrocyte enzyme are compared with those previously reported for mammalian liver ferrochelatase.
D000818:Animals; D002412:Cations / Q000494:pharmacology; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000201:enzymology*; D005227:Fatty Acids / Q000494:pharmacology; D005294:Ferrochelatase / Q000037:antagonists & inhibitors / Q000097:blood* / Q000302:isolation & purification; D007700:Kinetics; D008190:Lyases / Q000097:blood*; D010743:Phospholipids / Q000494:pharmacology; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D002412:Cations; D005227:Fatty Acids; D010743:Phospholipids; D013439:Sulfhydryl Reagents; D008190:Lyases; D005294:Ferrochelatase