title: Amylolytic activity in fish intestinal mucosa: temperature effects.
abstract: The activity, temperature characteristics and energy of activation of amylolytic enzymes in the intestinal mucosa were studied in six species of fish living in a boreal zone [burbot (Lota lota L.), northern pike (Exos lucius L.), perch (Perca fluviatilis L.), bream (Abramis brama L.), roach (Rutilis rutilis L.), and carp (Cyprinus carpio L.)] and in three species from tropical and subtropical areas [pilchard (Sardina pilchardus W.), jack mackerel (Trachurus trecae C.) and round sardinella (Sardinella aurita V.)]. The amylolytic activity correlated with the feeding habits: it was essentially lower in predators. The enzyme activity at low temperature, relative to the maximal activity, was correlated with the natural environmental temperature where the species lived. At low temperature the relative activity was higher in boreal fish than in tropical and subtropical fish. We found a breakpoint in the Arrhenius plots in all fish species, except for jack mackerel. The energy of activation in predators decreased below the breakpoint in the low-temperature region. The energy of activation in benthophages of the Aral-Ponto-Caspian area was lower at higher temperatures above the breakpoint. A reduction in activation energy in the range of physiological temperatures might indicate adaptation to the environmental temperature.
authors.affiliation: Laboratory of Fish Ecology, Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok 152742, Yaroslavl Province, Russia.
authors.forename: V
authors.initials: V
authors.lastname: Kuz'mina
authors.forename: L
authors.initials: L
authors.lastname: Glatman
authors.forename: V
authors.initials: V
authors.lastname: Drabkin
authors.forename: A
authors.initials: A
authors.lastname: Gelman
mesh_terms: D000681:Amylases / Q000378:metabolism*; D000818:Animals; D004064:Digestive System / Q000201:enzymology; D004789:Enzyme Activation; D029941:Fish Proteins / Q000378:metabolism; D005399:Fishes; D007413:Intestinal Mucosa / Q000201:enzymology*; D007700:Kinetics; D013045:Species Specificity; D013696:Temperature; D013816:Thermodynamics
chemical_list: D029941:Fish Proteins; D000681:Amylases