アワビにおける紅藻酸の生合成〔英文〕

概要

論文の詳細を見る
The capacity for the biosynthesis of D-rhodoic acid from taurine and pyruvic acid was studied in the tissues of abalone Halioris discus hannai using radioactive tracer methods. D-Rhodoic acid, a newly isolated marine natural product, has an interesting structure analogous to octopine, alanopine and strombine all of which are referred to as opines. Rhodoic acid has been shown to be one of the predominant nitrogenous components of muscle extractives of this abalone. Opines are generally considered to be end products of anaerobic glycolysis of molluscs. Muscle and mid-gut gland homogenates were incubated with 10μCi of radioactive taurine or pyruvate, with gentle shaking at 30°C for 1h. D-Rhodoic acid was isolated by ion exchange chromatography and recrystallized from aqueous ethanol Incorporation of radioactivity into n-rhadoic acid from both taurine and pyruvate was observed in the muscle, but not in the mid-gut gland. It is likely that this biosynthesis is mediated by the action of rhodoic acid dehydrogenase which catalyzes the reductative condensation reaction: taurine+pyruvate+NAAH ?? D-rhodoic acid+NAD++H2O.Since D-rhodoic acid is the most commonly observed opine in abalone Haliotis discus hannai, it can be assumed that this dehydrogenase has an important physiological role such as the main-tenance of cytoplasmic redox balance in the muscle tissue during periods of elevated glycolytic flux.