Biosynthese de la carcinine (β-alanyl-histamine)in vivo

Abstract

Carcinine was biosynthesized by Carcinus maenas from [14C]beta-alanine, [14C] histidine and [14C] histamine. Since carnosine (beta-alanyl-histidine) could not be detected in crab tissues, biosynthesis of carcinine could only be effected by direct coupling of beta-alanine and histamine resulting from histidine decarboxylation. Biosynthesis of carcinine was weak when [14C]beta-alanine and [14C] histidine were used as precursors. On the contrary when [14C] histamine was used, synthesis was important. Thus carcinine appears to be a product of histamine catabolism. After injecting [14C] histamine, radioactive carcinine was concentrated mainly in the heart and nervous system; nonmetabolized [14C] histamine was recovered mainly in the latter. The nervous system might therefore be the seat of carcinine biosynthesis and thus the site of action of histamine.

Mise en Evidence de la Carcinine Synthétase, une Nouvelle Enzyme Catalysant le Métabolisme de l'Histamine dans le Systeme Nerveux Central de Carcinus maenas

“…Chez Aplysia, l'histamine est apparue comme &ant un neurotransmet-. teur (Weinreich, 1977;McCaman et McKenna, 1978;Gruol et Weinreich, 1979a,b;McCaman et Weinreich, 1982, 1985. I1 est donc probable qu'il en soit de mime chez Carcinus, d'autant plus que l'histamine a ddja ktk impliqude comme neuromkdiateur dans le systime nerveux stomatogastrique de Palinurus (Claiborne et Selverston, 1984).…”

“…La carcinine synthktase diffkre dgalement de la carnosine synthktase, l'enzyme qui effectue la biosynth-&e de la carnosine chez les Vert6brks. Elle ne peut en effet kaliser la synth6se de la carnosine, que ce soit in vitro ou in vivo (Arnould, 1985). De mime, la carnosine synthktase, incubke en prksence d'histamine, ne peut effectuer celle de la carcinine (Honnishi et al, 1978).…”

“…Cette substance n'a pu &re impliquke jusqu'alors dans aucun phinomine physiologique (Arnould et Frentz, 1975b. L'itude de sa biosynthise in vivo a toutefois rkvilk, qu'aprks une injection d'histamine radioactive, le Crabe biosynthktisait de la carcinine marquke qui se concentrait non seulement dans le coeur mais kgalement dans le systkme nerveux; dans ce dernier tissu, elle ktait accompagnke de son prkcurseur radioactif (Arnould, 1985). Le systime nerveux pourrait donc &re le si2ge de la synthise de la carcinine et par suite le site d'action de l'histamine.…”

Drosophila tan encodes a novel hydrolase required in pigmentation and vision

“…There are no proteins related in sequence to Tan and Ebony in any vertebrate genome sequenced to date, and NBAD has not been found in vertebrates. Carcinine was originally characterized in the crab Carcinus maenas [38], but its biological function until recently has been a mystery. Carcinine possesses several pharmacological properties in mammals, including antioxidant effects [39] and cardiac vasodilation [40], but an endogenous role for this compound has not been demonstrated in any deuterostome.…”