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Corpus Systématique Animale

Titre du document

Thermal acclimation and kinetics of a trypsin-like protease in eucarid crustaceans

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Springer (journals)
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Mots-clés d'auteur
  • Digestive enzymes
  • Tryptic activity
  • Kinetic properties
  • Thermal acclimation
  • Eucarid crustaceans
  • BSA : bovine serum albumin
  • Ea : energy of activation
  • K m : Michaelis-Menten-constant
  • l -BAPA : N-benzoyl-l-arginine-p-nitroanilide
  • SB : soybean trypsin inhibitor
  • TLCK : N-tosyl-l-lysine chloromethyl ketone
  • TRIS : tris-(hydroxymethyl)-aminomethane
  • V max : maximal reaction velocity
Nom du fichier dans la ressource
  • Birgit Dittrich
  • Alfred-Wegener-Institut für Polar- und Meeresforschung, Columbusstraße, W-2850, Bremerhaven, FRG

The properties of a trypsin-like protease in homogenates from midgut glands and gastric fluids of crustaceans were analyzed with special emphasis on thermal acclimation. For comparison, four species from different climatic regions were investigated: Ocypode ryderi (tropical), Cancer pagurus (temperate), Meganyctiphanes norvegica (subarctic-boreal), and Chorismus antarcticus (Antarctic). The pH optimum of the hydrolysis of N-benzoyl-l-arginine-p-nitroanilide is similar in all four species; at 25°C it ranged between pH 8 and 9.5. In the gastric fluids, pH was between 6.4 (Chorismus) and 7.7 (Ocypode); under experimental conditions at 25?C, between 25% (Chorismus) and 95% (Ocypode) of maximal activity were observed at these pH values. Temperature optima of protease activity are independent from mean ambient temperature and were found to be around 50°C in Ocypode, 45°C in Cancer, 50–55°C in Meganyctiphanes, and 40°C in Chorismus. At temperatures near 0°C, temperate and tropical species show either a very low or even no activity at all, whereas the Antarctic and subarctic-boreal species display a residual activity of up to 15% of maximum activity. Under natural conditions, approximately 50% of maximal available enzymatic activity are eventually utilized. The kinetic parameters V max and K m depend on temperature and show distinct differences between the species. As an immediate response to temperature changes, the affinity for substrate decreases with elevated temperatures. Cold adaptation implies an effective utilization of energy in a low-energy system; the most prominent means of adaptation to low temperatures is the reduction of activation energy. Energies of activation in tropical temperate, and subarctic-boreal species (23.3–31.5 kJ·mol-1) are significantly higher than in the Antarctic species (11.9–13.6 kJ·mol-1). The enzymes were inhibited by N-tosyl-l-lysine chloromethyl ketone, copper sulfate, mercury chloride, and silver nitrate. In all enzymes, soybean trypsin inhibitor was the most effective inhibitor. Activation occurred after application of bovine serum albumin or calcium and magnesium chloride. The species-specific reactions after application of different protein or salt solutions support the hypothesis of decisive differences at the molecular level.

Catégories Science-Metrix
  • 1 - health sciences
  • 2 - biomedical research
  • 3 - physiology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - invertebres
Catégories Scopus
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Endocrinology
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Animal Science and Zoology
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Biochemistry
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Ecology, Evolution, Behavior and Systematics
  • 1 - Life Sciences ; 2 - Biochemistry, Genetics and Molecular Biology ; 3 - Physiology
Catégories WoS
  • 1 - science ; 2 - zoology
  • 1 - science ; 2 - physiology
Identifiant ISTEX

Journal of Comparative Physiology B

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  • Arthropodes
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