Nitric oxide synthase activity from a hematophagous insect salivary gland.
The salivary glands of the hematophagous insect, Rhodnius prolixus, contain a nitrosylhemeprotein that dissociates its ligand, NO, to the host tissues while the insect is searching for a blood meal. We now report a salivary nitric oxide synthase activity in this insect. The activity is dependent on NADPH, FAD, tetrahydrobiopterin, calmodulin, Ca2+, and converts arginine to citrulline while producing vasorelaxing activity. Molecular sieving indicates a molecular weight of 185 kDa, coeluting with a diaphorase activity. Results indicate similarity of this insect activity to the vertebrate constitutive NO synthase, suggesting NO synthesis is an evolutionary old biological pathway.
Ribeiro
J M
JM
Department of Entomology, University of Arizona, Tucson 85721.
Nussenzveig
R H
RH
D000594:Amino Acid Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001011:Aorta; D002851:Chromatography, High Pressure Liquid; D066298:In Vitro Techniques; D008970:Molecular Weight; D019001:Nitric Oxide Synthase; D011817:Rabbits; D012239:Rhodnius / Q000201:enzymology*; D012469:Salivary Glands / Q000201:enzymology*; D014664:Vasodilation
D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases