[Study of the carbohydrate components of the surface of S 1300 neuroblastoma cells with the use of cytochemical and lectin agglutination methods]. / Issledovanie uglevodnykh komponentov poverkhnosti kletok neiroblastomS 300 s pomoshch'iu metodov tsitokhimii i agliutinatsii lektinami.

The carbohydrate determinants of the cell surface of neuroblastoma C 1300 clone N 18 have been investigated by light microscopy with a panel of 11 lectins as cytochemical reagents. The expression of N- and O-glycanes with a predominance of 3-4 antigenic N-glycosyl chains was revealed. The characteristic feature of neuroblastoma cells is an abundance of an antigen A surface determinant. A strong correlation is shown between the intensity of lectin binding and index of cell agglutination. After the binding of lectins with living cells the lectin-receptor complexes are clustered, endocytosed and for 4 hours are concentrated as microvesicles in the cytoplasm compact area. Heterogeneity of the neuroblastoma cell population on the binding of peanut and Lens culinaris lectins is revealed.

[Interrelations of NAD and adenosine transformation in the rat liver]. / Vzaimovliianie prevrashchenii NAD i adenozina v pecheni krys.

The interrelationship of NAD and adenosine (inosine) conversions in the rat liver is investigated. The ratio of products of NAD+ conversions (ADP-ribose, inosine, hypoxanthine and ribose phosphates) are established. AMP and adenosine are not detected, which indicates an availability of different activities of the corresponding enzymes. It is shown that under conditions of the high inorganic phosphate concentration (33 mM) ribose-1-phosphate, formed in the purine nucleoside phosphorylase reaction, is accumulated due to the phosphoribomutase inhibition, but in the presence of NAD+ the utilization of ribose phosphate increases significantly. Nicotinamide inhibits the NAD+-glycohydrolase reaction in the system containing 33 mM phosphate, NAD+ and adenosine and simultaneously it lowers the utilization of ribose.

[Phosphate inhibition of the conversion of ribose-1-phosphate--a product of purine nucleoside phosphorylase splitting in the phosphoribomutase reaction]. / Tormozhenie fosfatom prevrashcheniia ribozo-1-fosfata--produkta purinnukleozidfosforilaznogo rasshchepleniia v fosforibomutaznoi reaktsii.

Different phosphate concentrations were studied for their effect on the degradation of adenosine by rat liver homogenates. It is shown that phosphate considerably inhibits the phosphoribomutase reaction without a significant effect on adenosine deaminase and purine nucleoside phosphorylase activities, that leads to the ribose-1-phosphate accumulation and to the disturbance of nucleoside utilization in reactions of the pentose phosphate pathway. It is supposed that the inhibition of the phosphoribomutase reaction by phosphate is important for regulation of nucleoside and nucleotide formation in a cell.