Ukrains'kyi biokhimichnyi zhurnal最新文献

According to the authors' observations, mixtures of fibrin monomer and fibrinogen-derived D fragment are gradually transformed into an equilibrium system when fibrin exists partly in a solid clot form and partly as a soluble material made unclottable by the influence of fragment D. The amount of such a soluble fibrin proved to be a linear function of the D fragment concentration. Three fibrin monomer preparations obtained in different ways were used. All of them showed similar properties as to the modifications with D fragment. The solubilzing activity of D fragment in the equilibrium system could sharply be raised by increasing ionic strength or pH. It is known that these medium changes produce the same stimulation effect on D fragment, being examined as an inhibitor of fibrin monomer polymerization. But the concentration dependences of the two activities of D fragment differ in principle.

The content of NAD+, NADH, NADP+, NADPH in the liver of normal, fasting rats, those on the low-carbohydrate diet and suffering from alloxan diabetes was studied as affected by nictotinamide. Changes in the NAD+ content, sum of nicotinamide coenzymes, the [NAD+] + [NADP+]/[NADH] +/- [NADPH] and [NAD+] + [NADH] (sum of nicotinamide coenzymes) ratios are mainly due to nicotinamide administration. Changes in the content of reduced forms of both nucleotides depend equally on nicotinamide administration and the physiological state of animals. Response of the rat organism to nicotinamide administration consists in a sharp intensification of NAD+ synthesis and in a less pronounced intensification of NADH, NADP+ and NADPH synthesis.

Heterogeneity of proteins of blood serum high-molecular fraction in healthy people, patients with cancer and those with pathologies of nonmalignant nature was studied by the method of disc electrophoresis in 4% polyacrylamide gel. It is established that under conditions of the experiment sharp differences are observed in heterogeneity of studied proteins manifesting in a growth of the discrete electrophoretic bands in disc electrophoregrams of high-molecular fractions of sera from the cancer patients. Disc electrophoregrams of proteins of the studied fractions from the sera of patients with nonmalignant pathologies also differ from those of control groups, though not so sharply as when comparing the preparations obtained from the sera of healthy people and cancer patients. Possible reasons of the observed differences are discussed.

Experiments were performed to detect "alkali" and "acid" carboxypeptidases in 39 enzymic preparations from fungi, yeast, actinomyces, bacteria and algae. Distribution of both types of carboxypeptidases is different: they are absent in the six of the studied sources, there are no "acid" carboxypeptidases in 11 sources and no "alkali" in nine ones. The largest amount of carboxypeptidases is in the objects from fungi and actinomycetes, the least, in those from bacteria and algae. There is no correlation between synthesis of these enzymes by one microorganism. Thus, fungi produce mainly "acid" enzymes, and actinomycetes only "alkali" ones. Asp. oryzae and Asp. flavus are powerful producers of the former, Streptomyces griseus of the latter. Specific activities 15-20 times as high as all the already studied ones are obtained for the preparations isolated from Str. griseus (protezym, proteinase-1, proteinase-3, crystal line complex of proteases). Carboxypeptidase of Str. griseus is relatively stable in comparison with "acid" ones in purification and concentration.

An intensified synthesis of glucose is observed in gluconeogenesis from endogenous precursor only for the first 30 min of perfusion. Pyruvate introduction into the medium raises phosphoenolpyruvate carboxykinase and fructose-1,6-diphosphatase activities in the liver and determines maintenance of the glucose formation high rate for 90 min of perfusion. 1,3-butanediol is found to have a stimulating effect on gluconeogenesis from pyruvate. Introduction of 1,3 bytanediol into perfusate decreases the redox state of free NAD-pairs, increases the content of phosphoenolpyruvate, malate. ATP and the phosphoenolpyruvate carboxykinase and fructose-1.6-diphosphatase activity in the perfused liver.

Isolated leukocytes with the presence of 14C-nicotinate in physiological concentrations (1 mg%) uptake it intensely from the dilute plasm for 6h. Dynamics of the uptake is characterized by two maxima (30-50 min and 3-5 h) which might reflect metabolic transformation of vitamin PP in leukocytes. Isolated erythrocytes and blood plasma proteins under these conditions accumulate the labelled vitamin in the largest amounts for first minutes of incubation without subsequent changes, accumulation of the labelled nicotinate by erythrocytes is 20 times as low as that by leukocytes. Kinetics of 14C-nicotinate uptake in increasing concentrations (from 4.0 up to 50.0 mM) by isolated leukocytes indicates to a system of this vitamin intake through the plasmatic membrane ensuring its intensive transport into cells with the present of 3.0-6.5 mM of nicotinic acid and a step inhibition of the label accumulation at higher concentrations which reflects decompensation of the vitamin-barrier function of the leukocytes plasma membranes with a rise in the nicotinate concentration in the medium from 6.5 to 16.3 mM the label accumulation is inhibited not only by leukocytes but also by erythrocytes. However the blood plasma proteins still bind 14C-nicotinate when it is present in the medium in linearly increasing high concentrations (16.0 = 50 mM).

Healing of the bone injury in rabbits was studied as affected by carbostimulin and its mixture with vitamin D3. Some biochemical indexes: the content of sialic acids, calcium and citric acid in blood serum of the animals, intensity of 14C incorporation from NaH14CO3 into the regenerated bone tissue and its proteins as well as histological studies, data, evidence for a positive effect of the mentioned preparations on the bone substance regeneration in the animals under experiment. So. the content of sialic acids in blood serum normalizes on the 10th day after the operation mostly in the animals which were administered the mixture of the preparations and in which the most pronounced hypercalcemia is observed. Incorporation of 14C from NaH14CO3 into the regenerated tissue and its proteins is most intensive in the same animals.

A simple, economical, highly productive and easily reproducible method is suggested for making 14C-labelled preparations of denaturated proteins to determine their radioactivity by the liquid scintillation counter. The advantages of the methods are as follows: it is possible for a short period of time to make a large number of preparations; the counted vessels are not contaminated during the work; scintillation liquid consumption is considerably reduced.

Under conditions of an increase in the carbonic acid concentration in blood of rabbits (experimental group) utilization of ammonia nitrogen administered to the organism intensifies and simultaneously the level of keto-acids in blood as well as of free amino acids and urea in the liver tissue increases. In these animals as compared to the control ones the content of glutamine in blood and in the liver tissue decreases; the level of alpha-glutarate and glutamate in the liver tissue increases and that of pyruvate lowers. An increase is also observed in reducing power of the liver and kidney cell cytoplasm.