Résumé
To investigate the effects of genistein (Gen) on the biosynthesis of N-glycolylneuraminic acid (Neu5Gc) in rats, 80 4-week-old male SD rats were randomly equally into the control and genistein groups. The rats of control and genistein groups were fed 5% ethanol and 300 mg/(kg·d) genistein respectively by gavage. The contents of Neu5Gc in hind leg muscle, kidney and liver tissues of rats were measured by using high performance liquid chromatography coupled with fluorescence detector (HPLC/FLD), and the mechanism of inhibition of Neu5Gc synthesis was investigated by using the molecular docking of Gen and sialyltransferase. On the 15th day, the content of Neu5Gc in hind leg muscle and liver tissues decreased 13.77% and 15.45%, respectively, and there was no significant change in the content of Neu5Gc in kidney tissues. On the 30th day, the content of Neu5Gc in liver tissues decreased 13.35%, however, there was no significant change in the content of Neu5Gc in kidney tissues and Neu5Gc was not detected in hind leg muscle. The content of Neu5Gc in hind leg muscle, kidney and liver tissues decreased respectively 32.65%, 32.78%, 16.80% and 12.72%, 11.42%, 12.30% while rats fed on the 45th and the 60th days. Genistein has formed the hydrogen bond with sialyltransferase activity site residues His319, Ser151, Gly293, Thr328 and formed a hydrophobic interactions with the residues His302, His301, Trp300, Ser271, Phe292, Thr328, Ser325 and Ile274. The results of molecular docking indicated that the weak intermolecular interaction was the main cause of genistein inhibiting sialyltransferase activity. The research results provided an experimental basis for the subsequent reduction of Neu5Gc in red meat before slaughter.
Sujets)
Animaux , Mâle , Rats , Régulation de l'expression des gènes codant pour des enzymes , Génistéine , Pharmacologie , Simulation de docking moléculaire , Acides neuraminiques , Métabolisme , Répartition aléatoire , Rat Sprague-Dawley , Transferases , MétabolismeRésumé
Urinary excretion of glycosaminoglycans [GAGS] and sialic acid [SA], as well as the activity of two renal enzymes related to glycoprotein metabolism, N-acetyl-beta-D-glucosaminidas [NAG] and beta-glucuronidase, were evaluated in 12 non-insulin dependent diabetic [NIDD] patients with normal range albuminuria and 12 control subjects. Diabetic patients excreted a significantly higher amount of GAGS and SA, and showed greater NAG activity. However, beta-glucuronidase activity showed non-significant increased levels. Moreover, no correspondence was found between the degree of metabolic control, as reflected by glycosylated hemoglobin [H[b]a1[a]-[c]], and GAGS, SA, NAG and beta glucuronidase emerged
Sujets)
Humains , Mâle , Femelle , Hexosaminidases , Acides neuraminiquesRésumé
Se estudiaron fracciones obtenidas de cerebro de raton albino suizo de 10 dias de edad desde el punto de vista fisico, quimico y biologico. Se confirmo su constitucion predominantemente proteica; cuando la alfa-quimotripsina actua sobre ellas por un lapso de 120 segundos, se liberan aminoacidos y/o pequenos peptidos, perdiendose la propiedad biologica de inhibir la hemaglutinacion del virus de la encefalitis equina del este. Se demostro que la fraccion biologicamente activa contiene glico y lipoproteinas. El tratamiento con SDA destruyo las lipotroteinas y expuso grupos glicoproteicos. Las fracciones calentadas evidenciaron mas grupos neuraminicos, que reaccionan con la o-fenantrolina, absorbiendo mas al UV. Se comprobo la presencia de lipidos neutros que no fueron identificados. El punto isoionico dio un valor de 4,16 +/- 0,17, indicativo de la presencia de grupos acidos