[Testing the activity of enzymes responsible for biosynthesis of purine nucleotides AIR-carboxylase and SAICAR-synthetase in human cell extracts]. / Testirovanie aktivnosti fermentov biosinteza purinovykh nukleotidov AIR-karboksilazy i SAIKAR-sintetazy v ékstraktakh kletok cheloveka.

Activities of AIR-carboxylase (ES 4.1.1.21) and SAICAR-synthetase (EC 6.3.2.6) were found in lysates of human erythrocytes, thrombocytes and leukocytes and in homogenate of the stomach biopsy sample. However, these activities were absent in blood plasma and bile. The human erythrocyte enzyme preparation, which had both activities, was isolated and purified about 200 times. The copurification of both activities and properties of the enzyme preparation suggest that two consecutive reactions of purine biosynthesis de novo (from AIR to SAICAR) in human cells are catalyzed by one bifunctional enzyme which is probably encoded by one gene.

[Degree of structural homology of lactoferrins from milk and neutrophilic granulocytes]. / O stepeni strukturnoi gomologii laktoferrinov moloka i neitrofil'nykh granulotsitov.

Some physico-chemical properties of human and pig lactoferrins from milk and neutrophilic granulocytes were compared. It was shown that the lactoferrins from different cell and tissue sources of the same species (humans or pigs) are identical in terms of electrophoretic mobility, molecular weight, iron-binding capacity, absorbance spectra, amino acid and sugar compositions and peptide maps. Human and pig lactoferrins show a high degree of structural homology (approximately 50%), but are immunochemically different.

[Various properties of cathepsin G and elastase from swine peripheral blood neutrophils]. / Nekotorye svoistva katepsina G i élastazy iz neitrofilov perifericheskoi krovi svin'i.

Using gel filtration through Sephadex G-100 and bioaffinity chromatography on contrical-Sepharose, cathepsin G and elastase were isolated from pig peripheral blood neutrophil granules and purified to homogeneity. Both enzymes hydrolyzed the total histone from calf thymus as well as synthetic substrates--tert-butoxy-L-alanine p-nitrophenyl ester (elastase) and benzoyltyrosine ethyl ester (cathepsin G). The use of natural and synthetic protease inhibitors showed that both enzymes were related to the group of serine proteases. The molecular mass of the cathepsin G subunit as determined by SDS polyacrylamide gel electrophoresis is 28-29 kD, that of elastase--30-31 kD. The pH optima for the hydrolysis of proteinaceous and synthetic substrates for cathepsin G and elastase are 8.0-8.5 and 7.0-7.5, respectively. The isoelectric points for elastase and cathepsin G are 9.7-10.0 and greater than 10, respectively; the temperature optima--30-40 degrees C and 50-60 degrees C, respectively. The amino acid composition of the two enzymes from pig granulocytes revealed a high content of arginine and was similar to that of human granulocytes.

[Differences in properties of creatine kinase BB from chicken tissues]. / Razlichiia v svoistvakh BB-kreatinkinaz iz tkanei kur.

BB-creatine phosphokinases (CPK-BB, EC 2.7.3.2) were isolated and purified from the chicken brain, heart and gizzard with specific activities 250-300 IU/mg and equal electrophoretic mobilities. Certain differences in thermal stability, activation energy, Km and optimal temperature of the CPK reaction are shown. The amino acid analysis has also revealed different content of certain amino acids in CPK-BB molecules. The obtained results confirm the existence of tissue-specific heterogeneity in CPK-BB which may be significant for functioning of the phosphocreatine-creatine phosphokinase system in different types of tissues.

[Specific acid-soluble chromatin protein synthesized in the rat liver after cortisone administration]. / Issledovanie spetsificheskogo kislotorastvorimogo belka khromatina, sinteziruiushchegosia v kletkakh pecheni krysy posle vvedeniia kortizona.

After cortisone injection, the content of the specific chromatin acid-soluble non-histone protein alpha is markedly increased in rat liver cells. The alpha-protein has been isolated in preparative amounts, its amino acid composition and some properties have been studied. It has been shown that the amino acid composition of protein alpha differs markedly from that of the HMG proteins, semi-histone A24, and of other non-histone proteins studied so far. Cortisone has been shown to induce the de novo synthesis of protein alpha. The alpha-protein is observed in transcriptionally active chromatin. The 3H-labeled hydrocortisone and dexamethasone bind mainly to this protein. The suggestion, that this protein participates in the regulation of transcriptional activity of liver cells in response to the hormonal stimulus is put forward.

[Nitrogen metabolism in elderly persons on a low-calorie diet]. / Sostoianie azotistogo obmena u lits pozhilogo vozrasta, poluchavshikh redutsirovannuiu po kaloriinosti dietu.

The clinical trials covered 9 men aged 58-73 years with daily energy losses of 2200-2350 kcal and given for 10 days the diet (1128 kcal/day) containing different food ingredients. A study was made of the main parameters of nitrogenous metabolism. During the time of being kept on a low-caloric diet, the test subjects lost 2.1 kg body mass. Excretion of total nitrogen dropped 34%, urea 57%. Excretion of creatinine appreciably rose (208% of the initial). The calculation of nitrogenous balance demonstrated protein deficiency to be equal to 209 g during experiments. The concentration of free amino acids in blood plasma decreased: that of replaceable by 29.5%, that of essential ones by 37.6%. It is assumed that the tension of body metabolism affected protein synthesis, whereas the protein quota in the diet did not appear sufficient for elderly subjects.