scholarly journals The release of N-acetyl- and N-glycolloyl-neuraminic acid from soluble complex carbohydrates and erythrocytes by bacterial, viral and mammalian sialidases

1981 ◽  
Vol 197 (2) ◽  
pp. 293-299 ◽  
Author(s):  
A P Corfield ◽  
R W Veh ◽  
M Wember ◽  
J C Michalski ◽  
R Schauer
Keyword(s):  
Submandibular Gland ◽  
Human Liver ◽  
Soluble Complex ◽  
Ganglioside Gm3 ◽  
Acetylneuraminic Acid ◽  
Liver Lysosomes ◽  
Acid Release ◽  
Physiological Systems ◽  
Virus Influenza

A series of substrates, sialyl(2 leads to 6)GalNAc and ganglioside GM3, containing either N-acetylneuraminic acid (AcNeu) or N-glycolloylneuraminic acid (GcNeu), has been prepared. The trisaccharide GcNeu(2 leads to 3)lactose was preapred by ozonolysis of GcNeu-GM3, and the disaccharides AcNeu(2 leads to 6)GalNAc and GcNeu(2 leads to 6)GalNAc were isolated from bovine submandibular-gland mucin by alkali elimination. Sialidases from Newcastle-disease virus, fowl-plague virus, influenza virus A2, Clostridium perfringens, Vibrio cholerae, Arthrobacter ureafaciens and human liver lysosomes were studied with the above substrates and all showed poorer cleavage of GcNeu-containing substrates when compared with the corresponding AcNeu-containing compounds. This was reflected in the Km and Vmax. values of these sialidases. Differences between viral and bacterial sialidases could be detected on the basis of their kinetic constants and time curves of sialic acid release. Preferred release of AcNeu relative to GcNeu was also observed with bovine submandibular gland mucin and a mixture of human and porcine erythrocytes, macromolecular substrates containing both AcNeu and GcNeu. The significance of differential cleavage of AcNeu and GcNeu by sialidases is considered together with examples of the role of GcNeu in physiologicaL systems.

scholarly journals Radioimmunochemical evidence for a role of carbohydrate in antigenic determinant(s) on human liver α-L-fucosidase

1984 ◽  
Vol 223 (2) ◽  
pp. 293-298 ◽  
Author(s):  
J A Alhadeff ◽  
G L Andrews-Smith
Keyword(s):  
Sialic Acid ◽  
Antigenic Determinant ◽  
Human Liver ◽  
Competitive Ability ◽  
Sialic Acids ◽  
Acetylneuraminic Acid ◽  
Colominic Acid ◽  
Sugar Derivatives ◽  
Radioimmunoassay Method

A competitive-binding radioimmunoassay method was employed to investigate the role of carbohydrate in antigenic determinant(s) of human liver alpha-L-fucosidase. Competition curves were used to quantify the concentrations of competitors needed to cause 30% inhibition of the precipitation of 125I-labelled alpha-L-fucosidase. The isoelectric forms of alpha-L-fucosidase, which are related by sialic acid residues, were separated preparatively and used as competitors in the radioimmunoassay. A pattern of increasing effectiveness as competitors with increasing acidity of the forms was found, suggesting that sialic acid may be involved in the antigenic determinant(s) of alpha-L-fucosidase. Specificity was exhibited when sugar and sugar derivatives were used as competitors in the radioimmunoassay: a 51-fold range of competitive ability was found, and sialic acids (N-acetylneuraminic acid and N-glycollylneuraminic acid) and colominic acid (a polymer of N-acetylneuraminic acid) were the best competitors. The results of our studies suggest that carbohydrate contributes to antigenic determinant(s) of alpha-L-fucosidase and that sialic acid is probably the major sugar involved.

scholarly journals Glucuronidation of hyodeoxycholic acid in human liver. Evidence for a selective role of UDP-glucuronosyltransferase 2B4.

1993 ◽  
Vol 268 (34) ◽  
pp. 25636-25642
Author(s):  
T Pillot ◽  
M Ouzzine ◽  
S Fournel-Gigleux ◽  
C Lafaurie ◽  
A Radominska ◽  
...  
Keyword(s):  
Human Liver ◽  
Hyodeoxycholic Acid ◽  
Udp Glucuronosyltransferase

Role of cytochrome P450IIIA4 in the metabolism of the pyrrolizidine alkaloid senecionine in human liver

1991 ◽  
Vol 12 (3) ◽  
pp. 515-519 ◽  
Author(s):  
Cristobal L. Miranda ◽  
Ralph L. Reed ◽  
F. Peter Guengerich ◽  
Donald R. Buhler
Keyword(s):  
Human Liver ◽  
Pyrrolizidine Alkaloid

scholarly journals Detection of CMP-N-acetylneuraminic acid hydroxylase activity in fractionated mouse liver

1989 ◽  
Vol 263 (2) ◽  
pp. 355-363 ◽  
Author(s):  
L Shaw ◽  
R Schauer
Keyword(s):  
Submandibular Gland ◽  
Mouse Liver ◽  
High Speed ◽  
Metal Salts ◽  
Supernatant Fraction ◽  
Inhibitory Influence ◽  
Hydroxylase Activity ◽  
Acetylneuraminic Acid ◽  
Liver Homogenates ◽  
High Speed Supernatant

The finding that N-glycoloylneuraminic acid (Neu5Gc) in pig submandibular gland is synthesized by hydroxylation of the sugar nucleotide CMP-Neu5Ac [Shaw & Schauer (1988) Biol. Chem. Hoppe-Seyler 369, 477-486] prompted us to investigate further the biosynthesis of this sialic acid in mouse liver. Free [14C]Neu5Ac, CMP-[14C]Neu5Ac and [14C]Neu5Ac glycosidically bound by Gal alpha 2-3- and Gal alpha 2-6-GlcNAc beta 1-4 linkages to fetuin were employed as potential substrates in experiments with fractionated mouse liver homogenates. The only substrate to be hydroxylated was the CMP-Neu5Ac glycoside. The product of the reaction was identified by chemical and enzymic methods as CMP-Neu5Gc. All of the CMP-Neu5Ac hydroxylase activity was detected in the high-speed supernatant fraction. The hydroxylase required a reduced nicotinamide nucleotide [NAD(P)H] coenzyme and molecular oxygen for activity. Furthermore, the activity of this enzyme was enhanced by exogenously added Fe2+ or Fe3+ ions, all other metal salts tested having a negligible or inhibitory influence. This hydroxylase is therefore tentatively classified as a monooxygenase. The cofactor requirement and CMP-Neu5Ac substrate specificity are identical to those of the enzyme in high-speed supernatants of pig submandibular gland, suggesting that this is a common route of Neu5Gc biosynthesis. The relevance of these results to the regulation of Neu5Gc expression in sialoglycoconjugates is discussed.

scholarly journals The role of nitric oxide in the control of protein secretion in the submandibular gland of the cat

1995 ◽  
Vol 80 (6) ◽  
pp. 1019-1030 ◽  
Author(s):  
AD Buckle ◽  
SJ Parker ◽  
SR Bloom ◽  
AV Edwards
Keyword(s):  
Nitric Oxide ◽  
Submandibular Gland ◽  
Protein Secretion

scholarly journals The Role of CYP2C8 and CYP2C9 Genotypes in Losartan-Dependent Inhibition of Paclitaxel Metabolism in Human Liver Microsomes

2015 ◽  
Vol 118 (6) ◽  
pp. 408-414 ◽  
Author(s):  
Yuji Mukai ◽  
Asuna Senda ◽  
Takaki Toda ◽  
Erik Eliasson ◽  
Anders Rane ◽  
...  
Keyword(s):  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Dependent Inhibition

Metabolism of dexfenfluramine in human liver microsomes and by recombinant enzymes: role of CYP2D6 and 1A2

1998 ◽  
Vol 8 (5) ◽  
pp. 423-432 ◽  
Author(s):  
Victoria S. Haritos ◽  
Michael S. Ching ◽  
Hany Ghabrial ◽  
Annette S. Gross ◽  
P??ivi Taavitsainen ◽  
...  
Keyword(s):  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Recombinant Enzymes
Sign in / Sign up

Export Citation Format

Share Document