title: The prosthetic group of milk lactoperoxidase is protoheme IX.
abstract: The prosthetic group of milk lactoperoxidase has been isolated from a Pronase hydrolysate of the enzyme and identified spectroscopically and chromatographically as protoheme IX. Partial degradation of the heme occurred during the proteolysis, possibly as a result of coupled oxidation in the presence of glycine and oxygen. The heme is assumed to be buried in the protein molecule in a crevice, which allows ligands to bind to the iron on one side only. The pyridine hemochrome of lactoperoxidase with alpha-band at 563 nm is interpreted as a mixed ligand complex with pyridine on one side of the heme and a ligand originating from the protein on the other. No experimental evidence supports the view that the heme is covalently bound to the protein through an ester linkage.
mesh_terms: D000818:Animals; D002417:Cattle; D002855:Chromatography, Thin Layer; D005260:Female; D006418:Heme; D007784:Lactoperoxidase; D008892:Milk / Q000201:enzymology*; D010544:Peroxidases; D011166:Porphyrins; D011402:Pronase; D013053:Spectrophotometry
chemical_list: D011166:Porphyrins; D006418:Heme; D007784:Lactoperoxidase; D010544:Peroxidases; D011402:Pronase