Catalase-like activity of bovine met-hemoglobin: interaction with the pseudo-catalytic peroxidation of anthracene traces in aqueous medium.
Hemoglobin is a member of the hemoprotein superfamily whose main role is to transport O(2) in vertebrate organisms. It has two known promiscuous enzymatic activities, peroxidase and oxygenase. Here we show for the first time that bovine hemoglobin also presents a catalase-like activity characterized by a V(max )of 344 microM/min, a K(M )of 24 mM and a k(cat) equal to 115/min. For high anthracene and hemoglobin concentrations and low hydrogen peroxide concentrations, this activity inhibits the expected oxidation of anthracene, which occurs through a peroxidase-like mechanism. Anthracene belongs to the polycyclic aromatic hydrocarbon (PAH) family whose members are carcinogenic and persistent pollutants found in industrial waste waters. Our results show that anthracene oxidation by hemoglobin and hydrogen peroxide follows a typical bi-bi ping-pong mechanism with a V(max) equal to 0.250 microM/min, K(M(H2O2) )of 80 microM, K(M(ANT)) of 1.1 microM and k(cat) of 0.17/min. The oxidation of anthracene is shown to be pseudo-catalytic because an excess of hemoglobin and hydrogen peroxide is required to make PAH completely disappear. Thus, bovine hemoglobin presents, in different degrees, all the catalytic activities of the hemoprotein group, which makes it a very interesting protein for biotechnological processes and one with which structure-activity relationships can be studied.
Paco
Laveille
L
Institut Charles Gerhardt Montpellier, Equipe des Matériaux Avancés pour la Catalyse et la Santé, UMR 5253 CNRS/ENSCM/UM2/UM1, 34296 Montpellier, France.
Galarneau
Anne
A
Drone
Jullien
J
Fajula
François
F
Bailly
Carole
C
Pulvin
Sylviane
S
Thomas
Daniel
D
D000818:Animals; D000873:Anthracenes / Q000737:chemistry / Q000378:metabolism; D001709:Biotechnology; D002374:Catalase / Q000378:metabolism*; D002417:Cattle; D006861:Hydrogen Peroxide / Q000378:metabolism; D008706:Methemoglobin / Q000378:metabolism*; D008954:Models, Biological; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism
D000873:Anthracenes; D011084:Polycyclic Aromatic Hydrocarbons; D008706:Methemoglobin; D006861:Hydrogen Peroxide; D002374:Catalase; C034020:anthracene