Purification and properties of bromoperoxidase from Penicillus capitatus.

A bromoperoxidase has been isolated and purified from the marine green algae, Penicillus capitatus. The purified enzyme is homogenous as determined by polyacrylamide gel electrophoresis and ultracentrifugation. Bromoperoxidase can utilize bromide ions in the presence of hydrogen peroxide and a halogen acceptor for the catalytic formation of carbon-halogen bonds. Based on equilibrium ultracentrifugation results the molecular weight of bromoperoxidase is 97,600. Sodium dodecyl sulfate polyacrylamide gel electrophoresis shows a single band having the mobility of a 55,000 molecular weight species. We thus conclude that bromoperoxidase exists in solution as a dimeric species. The heme prosthetic group of bromoperoxidase is ferriprotoporphyrin IX. The spectral properties of the native and reduced enzyme and cyanide, azide, and carbonmonoxy-reduced derivatives are reported. Amino acid analyses indicate that bromoperoxidase is rich in aspartic and glutamic acid residues, while being deficient in basic amino acid residues. In terms of enzymic activity, comparative data places bromoperoxidase closer to horseradish peroxidase than to chloroperoxidase and catalase.