THE SALIVARY CATECHOL OXIDASE PEROXIDASE-ACTIVITIES OF THE MOSQUITO ANOPHELES-ALBIMANUS

Salivary gland homogenates from adult female Anopheles albimanus mosqu itoes relaxed aortic rings preconstricted with noradrenaline (NA). Thi s relaxation is slow and is due to destruction of NA. Incubation of NA with the homogenate yielded a product with a spectrum consistent with the corresponding adrenochrome. Oxidation of NA was enhanced by a sup eroxide generation system and inhibited by the combined action of supe roxide dismutase and catalase. Additionally, peroxidase activity on bo th synthetic (o-dianisidine) and biologically active (serotonin) subst rates was also present in the salivary gland homogenates, this latter activity requiring hydrogen peroxide. Noradrenaline oxidation, seroton in and o-dianisidine peroxidation and vasodilation all co-elute with a heme protein of relative molecular mass 50000, as determined by molec ular sieving chromatography. Peroxidase activity was localized in the posterior (female-specific) lobes of salivary glands and was also dete cted in nitrocellulose membranes probed by hungry mosquitoes. Protein and peroxidase activities were significantly lower in salivary glands of mosquitoes after probing and feeding on blood. It is suggested that adult female Anopheles albimanus mosquitoes contain a salivary heme p eroxidase that functions during blood finding and blood feeding by des troying hemostatically active biogenic amines released by the vertebra te host during tissue destruction.