Studies on metabolic properties in the Northern Krill, Meganyctiphanes norvegica (Crustacea, Euphausiacea): influence of nutrition and season on pyruvate kinase - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY Année : 2000

Studies on metabolic properties in the Northern Krill, Meganyctiphanes norvegica (Crustacea, Euphausiacea): influence of nutrition and season on pyruvate kinase

M Salomon
  • Fonction : Auteur
F Buchholz
  • Fonction : Auteur

Résumé

The specific activity and the kinetic properties of partly purified pyruvate kinase (PK) (EC 2.7.1.40) from the Northern Krill, Meganyctiphanes norvegica, were investigated in relation to varying food resources. In order to evaluate the effect of starvation on the total energy metabolism, the respiration rates of fed and unfed krill were determined. The FPLC-elution profile of PK displayed two distinct peaks - PK I and II. The first isoform represented 80% of the total PK activity in the organism, and 20% was contributed by the second isoform. PK I was inhibited by ATP but was not influenced by fructose-1,6-bisphosphate (FBP). In contrast, PK II showed ATP inhibition and up to 2.5-fold increased activity by addition of 17 mu mol.l(-1) FBP. The Michaelis-Menten constants of both isoforms were 2-10-fold higher for ADP than for phosphoenolpyruvate (PEP). Alanine showed no regulatory effect on PK I and II. In specimens starved for 7 days oxygen consumption decreased by 20%. Neither the feeding experiments nor the animals captured in the field during low and high productive seasons indicate that PK properties of M. norvegica are modified in relation to food supply. Accordingly, alternative mechanisms are involved in the depression of the metabolic rate in terms of oxygen consumption. (C) 2000 Elsevier Science Inc. All rights reserved.

Domaines

Océanographie

Dates et versions

hal-03483074 , version 1 (16-12-2021)

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Citer

M Salomon, P Mayzaud, F Buchholz. Studies on metabolic properties in the Northern Krill, Meganyctiphanes norvegica (Crustacea, Euphausiacea): influence of nutrition and season on pyruvate kinase. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY, 2000, 127 (4), pp.505-514. ⟨10.1016/S1095-6433(00)00281-6⟩. ⟨hal-03483074⟩
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