PubMed Health⌕ Search

Biomedical subjects

A M Ugolev

Publications and source records attributed to A M Ugolev.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1979

[Glycerinized models of enterocytes and several of their properties].

The method for the preparation of glycerol-treated models of the enterocytes with preserved membrane has been described. Using such a simplified model of the enterocyte suspension allows membrane digestion and enzyme properties to be studied. Moreover, preserving the important properties of the native isolated cells the glycerol-treated enterocytes have a number of essential advantages as compared with other known preparations of the small intestinal mucosa. Some characteristics of the glycerol-treated models of the enterocytes have been described in the paper.

Amylases↗
PubMed1978

[Interrelationships between the enzymatic functions of the pancreas and small intestine during adaptive processes].

In rats fed for 4, 15, and 30 days with increased amount of proteins, lipids, and carbohydrates, considerable shifts occurred in activity of enzymes of the pancreas (amylase, protease, and lipase) and small intestine (gamma--amylase, maltase group, invertase, peptidhydrolase, monoglyceriflipase). Mathematical analysis suggested a close connection between the adaptive shifts in the enzyme systems maintaining the lumen and the membrane types of digestion. The protein diet augments the proteolytic enzyme chain the lipid diet--the lipolytic chain, and the carbohydrate diet--the carbohydrate chain. The shifts should be regarded as an integrative adaptive response of the enzyme spectrum of the pancreas and small intestine to alterations in the food composition.

Amylases↗
PubMed1978

A model of chronic alcohol intake under free-choice conditions.

The preference of 42 Wistar male rats for alcoholic or non-alcoholic solutions of glucose was studied. Preference for the left or right position of drinking tubes did not appreciably influence the choice between the unequal solutions. Within the same strain of rats the majority of the animals had a high and a minority a low level of consumption of the glucose-alcohol solution. These groups were found only under conditions of systematic experimentation and the properties of each group became more marked in the course of these experiments.

Alcohol Drinking↗
PubMed1977

Membrane and intracellular hydrolysis of peptides: differentiation, role and interrelations with transport.

The possible relative importance of the membrane and intracellular peptidases of the enterocytes in splitting dietary peptides to amino acids has been analysed. On the anoxic criterion, membrane hydrolysis was found to be predominant. Model experiments revealed cooperative interactions between the membrane enzyme and the coupled transport system. This cooperativity allows the main characteristics of oligomer transport to be described in terms of membrane digestion. Comparison of the behaviour of membrane and intracellular peptidase under different conditions has shown that the former are largely involved in digestion and the latter in intracellular metabolism. It is suggested that the efficiency of the membrane system is high enough to account for the hydrolysis of protein, especially taking into account the stimulation of enzyme processes in the brush border that occurs after ingestion of protein and carbohydrate. A sequential model based on the concept of three interacting enzyme layers (glycocalyx, lipoprotein membrane and cytosol) is presented.

Allosteric Regulation↗
PubMed1977

[Structural and functional integration of the processes of membrane hydrolysis and transport ("permeome" hypothesis)].

It was suggested and experimentally proved that the transport system's input is a part of an enzyme-transport ensemble and an allosteric regulator of enzyme activity. In special experiments, a typical for cooperation sygmoidal kinetics of saccharose and maltose hydrolysis was shown, as well as of their hydrolysis products transport, if the enzyme is involved in the actively transporting intestine mucosa. On the contrary, it is the hyperbolic curve which is specific for isolated digestive enzymes and for glucose accumulation. Replacement of oxygen with nitrogen and specific blockage of the glucose transporting agent with floridzine leads to disappearance or sharp reducing of the sygmoidality. The term "ergome" is suggested for designation of the minimal ensemble of elements able to carry out an elementary physiological process, the term "permeome"--for the transporting ergome.

Allosteric Regulation↗