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Biomedical subjects

V V Egorova

Publications and source records attributed to V V Egorova.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Radial and proximo-distal distribution of hydrolytic enzymes in the small intestine at rest and during digestion].

Alpha-amylase was present in considerable amount in the chyme in rats both at rest and during digestion, in the latter case its level being increased. Activity of intrinsic intestinal enzymes dominated in the homogenate of the mucosa. Transition from fasting to feeding and digestion increased the level of alkaline phosphatase and dipeptidase activities in the homogenate of the mucosa. The data obtained suggest the final stages of biopolymers' hydrolysis to be localized in various enterocyte structures. The surface mucus, owing to absorbed pancreatic enzymes, binding proteins and other types of physiologically active molecules, is assumed to play the role of a specific molecular filter and take part in the initial stages of digestion.

Animals↗
PubMed1986

[Physiology of the hydrophobic domain].

The role of the hydrophobic part in the functioning of some amphipathic enterocyte enzymes has been studied in various animal species (fish, mammals, insects). Kinetic (Km, Vmax, pHopt) and regulatory properties of membrane, detergent and protease forms of carbohydrases, alkaline phosphatase and alanine aminopeptidase were compared. All the species under study showed significant differences among these forms of enzymes. The data obtained demonstrate the important role of the hydrophobic anchor in forming both catalytic and regulatory properties of enzymes.

Alkaline Phosphatase↗
PubMed1986

[Alanine aminopeptidases from small intestinal mucosa of dogs, rabbits and trout. I. Characterization of the "protease forms"].

Alanine aminopeptidases from the mucous membranes of the small intestines of dog, rabbit and trout were concentrated 200 fold in the case of dog and rabbit, and 15 fold in the case of trout. The enzymes were analyzed with respect to substrate specificity, effector behaviour, optimum pH value, Michaelis constants and molecular weight. The values obtained for these enzymes are not consistent in all points with those found for alanine aminopeptidases isolated from the mucous membrane of human jejunum and ileum.

Aminopeptidases↗
PubMed1986

[Alanine aminopeptidase from small intestinal mucosa of dogs, rabbits and trout. II. Behaviour of "detergent forms"].

Alanine aminopeptidases from the mucous membranes of the small intestines of dog, rabbit and trout were purified as detergent forms. The enzymes obtained were characterized with respect to substrate specificity, effector behaviour, Michaelis constants, molecular weight and temperature dependence. In comparison to data of the protease forms of the alanine aminopeptidases, differences could be demonstrated.

Aminopeptidases↗
PubMed1986

[Hydrolases of the digestive organs during ontogenesis].

A wide variety of enzymes actualizing membrane hydrolysis of nutrients and their distribution in the gastro-intestinal tract were characterized in one-day old and adult rats and rabbits. The comparison of enzymatic activities of various animal species suggests that some enzymes are responsible for the adaptation to milk diet (lactase), others--to definitive nutrition (invertase, maltase). A number of enzymes (peptidase, alkaline phosphatase) do not depend on the type of nutrition. High activity of some hydrolases in the colon has been demonstrated confirming the A. M. Ugolev hypothesis of its digestive functions in the early ontogenesis.

Age Factors↗
PubMed1985

Comparative characterization of some enterocytic brush border membrane enzymes in mammals and fish.

The properties of the detergent- and protease-forms of alanine aminopeptidase and alkaline phosphatase of enterocytes in rabbits, cows, dogs and trout were investigated. The hydrophobic parts of the enzymes perform not only anchor functions, but also regulatory ones. It is suggested that these functions are of peculiar regularity, but vary in different enzymes of one species as well as in the same enzyme of different species.

Alkaline Phosphatase↗
PubMed1984

[Purification of a special estrogen-binding protein from the liver of rats by affinity chromatography on estradiol sepharose].

A procedure has been developed for purification of a special rat liver estrogen-binding protein. It includes protein precipitation by ammonium sulfate, gel filtration, ion exchange chromatography, and affinity chromatography on estradiol sepharose. The protein is purified 2260-fold with a 27% yield. Upon electrophoresis in 10% PAG in the presence of sodium dodecylsulfate the protein gives one polypeptide strip with a molecular weight of 31.200 +/- 400 dalton.

Animals↗
PubMed1983

Comparative-molecular characterization of membrane digestion in fish and mammals.

The role of different parts of enzyme-membrane complexes in relation to the digestive membrane enzymes in some fish species of varying ecology are compared with those of the rat as a representative of homoiothermic animal. The activity of enzymes in various animal species at 25 degrees C, t degrees-function, Eact, Km and Vmax for different forms of alkaline phosphatase, sucrase and maltase is described. Adaptibility to a specific temperature is determined by both the phospholipid matrix and the enzyme protein globule including its hydrophobic part; their roles in adaptation of different enzymes (carbohydrases and alkaline phosphatase) differ.

Alkaline Phosphatase↗
PubMed1979

[Regulatory properties of the intestinal enzymes of higher and lower animals as an adaptation mechanism in digestion and absorption].

It is shown that certain key enzymes in membranous digestion (alkaline phosphatase, peptidase, gamma-amylase) are allosteric and ensure the autoregulation and the homoeostasis of the final stages of hydrolysis and of the initial stages of nutrient transport. This mechanism was evidenced not only in vertebrates (mammals, birds, fishes), but also in invertebrates (drosophilae). The comparison of the triton and trypsin forms of the enzymes permitted to locate centres of regulation in the hydrophobic parts of amphipathetic enzymes (as illustrated by the examples of alkaline phosphatase and gamma-amylase of of the rat and of the drosophila). A considerable variability of the regulatory characteristics of the enzymes under investigation was demonstrated in the different varieties of drosophila. The authors present a hypothesis on the role of the regulatory properties of digestive enzymes in the physiology and the pathology of the digestive and transport systems of the small intestine.

Adaptation, Physiological↗
PubMed1979

Catalytic and regulatory properties of the Triton and trypsin forms of the brush border hydrolases.

Amphipathic enzymes, invertase (EC 3.2.1.26), 8-amylase (EC 3.2.1.3), and alkaline phosphatase (EC 3.1.3.1), were purified from the rat small intestinal mucosa as trypsin and Triton forms, the catalytic and regulatory characteristics of which were compared in rats and in drosophila. Differences in the catalytic propertiis of the two enzyme forms were demonstrated, which suggested that the hydrophobic part of the enzyme was involved in maintaining optimal conformation of the catalytic part. Many modifiers have beenfound to influence the Triton rather than the trypsin form of the enzyme. It is therefore suggested that the hydrophobic sub-units of the enzymes might be involved in transmitting information from the cytoplasm into the external surface of the membrane, the cell in this way regulating the activity of surface enzymes. If this is indeed the case, it is suggested that the hydrophobic part performs functions not only of external but also of internal regulation.

Alkaline Phosphatase↗