R. Nakamura

Rhodium-Catalyzed Reductive Cleavage of Carbon−Cyano Bonds with Hydrosilane: A Catalytic Protocol for Removal of Cyano Groups

The rhodium-catalyzed reductive cleavage of carbon-cyano bonds is developed using hydrosilane as a mild reducing agent. A wide range of nitriles, including aryl, benzyl, and beta-hydrogen containing alkyl cyanides are applicable to this decyanation reaction. The method can also be applied to organic synthesis; the use of benzyl cyanide as a benzyl anion equivalent and the use of a cyano group as a removable ortho-directing group are demonstrated.

Alkaline and acid phosphatase activities in the gingiva and alveolar bone in scurvy.

Abstract Techniques for measuring the enzyme activity of alkaline and acid phosphatases in the gingiva and alveolar bone of guinea pigs are described. Assays of both enzymes were also carried out for liver, kidney, small intestine and femoral cortex. When the activity of alkaline phosphatase was expressed on the basis of unit weight of wet tissue, gingiva and small intestine showed a high value, kidney and alveolar bone an intermediate one, and femoral cortex and liver remarkably low levels. For alkaline phosphatase expressed on the basis of extracted protein, alveolar bone and gingiva, respectively, possessed about 560 and 90 times higher activity than liver which had the lowest value of all tissues studied. When acid phosphatase activity was expressed as units per weight of wet tissue, gingiva and liver showed a high level, kidney and small intestine being almost as high, while a remarkably low level was detected in alveolar bone and femoral cortex. The activity expressed on the basis of extracted protein was almost identical for liver, kidney, femoral cortex and small intestine. Gingiva and alveolar bone had approximately 2.5 and 1.4 times greater activity than liver, respectively. The alkaline phosphatase activity of gingiva, alveolar bone and femoral cortex decreased strikingly after 3 weeks of scorbutic regime. No significant change was found in liver and kidney, though small intestine showed a slight decrease. The acid phosphatase activity of gingiva, alveolar bone, femoral cortex, small intestine and liver showed a significant increase in scurvy, but kidney did not exhibit a significant change.

α-l-fucosidase activity of some oral streptococci

Abstract The presence of α- l -fucosidase in the extracellular or intracellular fraction from oral streptococci was sought using porcine submandibular glycoprotein (PSG) and p- nitrophenyl -α- l - fucoside (p-NPF) as substrates. Extracellular fucosidase activity was found only in Streptococcus sanguis ATCC 10557 and Streptococcus mitis ATCC 9811 using PSG, but not p-NPF. The intracellular fractions of several strains possessed fucosidase activity against the PSG and/or p-NPF.

Citric acid metabolism in scurvy

Abstract Aconitase and TPN-linked iso citric dehydrogenase activities in the supernatant fraction of the gingiva and alveolar bone of scorbutic guinea pigs were evaluated. The activities of both enzymes in the heart, liver, kidney, adrenal gland, pancreas, spleen and femoral cortex were also studied. The aconitase activity of the kidney, alveolar bone, femur cortex and heart decreased to about 75 per cent of the normal value after 3 weeks of scorbutic regime. However, the other tissues did not exhibit significant changes. Elevated citrate level was also found in kidney, alveolar bone and femur cortex in which the aconitase activity was markedly decreased. Prolonged administration of insulin to scorbutic animals restored both the depressed aconitase activity and the elevated citrate content in the kidney and bone tissues significantly to normal level. No significant change in the activity of iso citric dehydrogenase was observed in any of the tissues of scorbutic animals.

Isocitric dehydrogenase activity in the gingiva and alveolar bone of the guinea pig

Abstract A technique for measuring the enzyme activity of TPN-linked isocitric dehydrogenase in the gingiva and alveolar bone of normal guinea pigs has been described. The enzyme activity in the heart, kidney, liver and femur cortex were also determined as controls. When enzyme activity was expressed on the weight of the wet tissue, liver, heart and kidney showed a high value, gingiva a relatively low one, and alveolar bone and femur cortex remarkably low levels. The activities expressed on the basis of content of extracted protein were also high for heart, kidney and liver, those of alveolar bone, femur cortex and gingiva were approximately equal and only some 10 per cent of the level in the more active tissues.

α-l-Fucosidase activity in human saliva and dental plaque

Abstract α- l -Fucosidase activities were determined using p- nitrophenyl -α- l - fucoside (p- NPF ) and de-sialized porcine submandibular glycoprotein (DS-PSG) as substrates. Dental plaque and whole saliva possessed enzyme activity against both substrates. Parotid and submaxillary-sublingual saliva exhibited the activity on p-NPF, but did not on DS-PSG.

Purification and Some Properties of a-L-Fucosidase Isolated from Streptococcus sanguis

α-L-Fucosidase acting on naturally occurring substrates was highly purified from the growth culture of Streptococcus sanguis ATCC 10557. The molecular weight of the enzyme was approximately 120,000 and the optimal pH was at 5.5. The purified enzyme showed specificity toward the linkage of α-(1→2) fucosides in oligosaccharides and glycoproteins. The enzyme released L-fucose from glycoprotein in human parotid saliva.

Hydrolysis of milk oligosaccharides by the oral bacterium Streptococcus sanguis atcc 10557.

Abstract The sequential degradation of oligosaccharide chains by Strep, sanguis ATCC 10557 was studied using milk oligosaccharides (lacto-N-fucopentaitols) labelled by reduction with tritiated borohydride as substrates. The culture supernatant hydrolysed lacto-N-efucopentaitol I, II or III, and yielded radioactive tetrasaccharides, disaccharides and monosaccharides. Galactonolactone inhibited the hydrolysis of galactosyl β1–3 or -4 N-acetylglucosamine linkage in lacto-N-fucopentaitol II or III, and the tetrasaccharide increased consequently. It is deduced that the exo-type of glycosidases secreated by Strep, sanguis ATCC 10557 sequentially degrade the glycosidic linkages from non-reducing sites of milk oligosaccharides and that the carbohydrate units of saliva glycoproteins may be hydrolysed by oral bacteria.

Changes of Serological Activity by α-L-Fucosidase Isolated from Streptococcus sanguis ATCC 10557

a-L-Fucosidase isolated from the growth culture of Streptococcus sanguis ATCC 10557 acted on H- and Leb-blood group substances in porcine gastric lining, human gastric lining, human ovarian cyst fluid and human whole saliva, with consequent loss of H- and Leb -activities and a concomitant increase of Lea activity.

Citrate Synthase Activity in Periodontal Tissues

SYNOPSIS IN INTERLINGUA ACTIVITATE DE SYNTHASE DE CITRATO IN Tissu PERIODONTAL.—Con le utilisation del sensibile e convenibile essayo a fissura per ester thiolic, le activitate de synthase de citrato (EC 4.1.3.7; oxaloacetato-lyase de citrato) esseva determinate in le fractiones supematante de gingiva, osso alveolar, e altere tissus de porco de India. Cortice de femore, osso alveolar, gingiva, hepate, e ren possedeva approximativemente 1/60, 1/33, 1/24, 1/12, e 1/4, respectivemente, le activitate medie per mg de extrahite proteina cardiac. Le activitate exprimite a base de unitates de peso de tissu humide esseva etiam le plus alte pro le corde. Illo de osso alveolar e de gingiva esseva approximativemente 1/440 e 1/40, respectivemente, del correspondente valor trovate pro le corde.