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Aminopeptidase N Activity (aminopeptidase_n + activity)
Selected AbstractsThiolation of polycarbophil enhances its inhibition of intestinal brush border membrane bound aminopeptidase NJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 11 2001Andreas Bernkop-Schnürch Abstract The purpose of this study was to evaluate the potential of polycarbophil,cysteine conjugates (PCP,Cys) as an oral excipient to protect leucine enkephalin (leu-enkp) from enzymatic degradation by the intestinal mucosa. Cysteine was covalently linked to polycarbophil by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDAC). Inhibitory activity was tested towards isolated aminopeptidase N and excised intact pig intestinal mucosa, with native mucus. Aminopeptidase N activity was assayed spectrophotometrically using L -leucine p -nitroanilide (leu-pNA) as a synthetic substrate and against the model peptide drug leu-enkp, by high-performance liquid chromatography (HPLC). Free cysteine at 6.3 and 63 ,M (pH 6) significantly (p,<,0.05) inhibited aminopeptidase N activity, and PCP,Cys (0.25% w/v, pH 6) had a significantly (p,<,0.05) greater inhibitory effect than PCP on the aminopeptidase N activity towards both substrates. PCP,Cys completely protected leu-enkp against aminopeptidase N activity over a 2-h incubation period, whereas 83,±,4 and 60,±,7% remained stable in the presence of PCP and buffer only, respectively. Leu-enkp in the absence and presence of PCP (0.25% w/v) at pH 6 was completely digested by the intact intestinal mucosa at the 60- and 90-min incubation time points, respectively, whereas in the presence of PCP,Cys (0.25% w/v, pH 6) 11,±,3.5% of leu-enkp remained at the 120-min time point. Thiolation of PCP increased the stability of leu-enkp against the enzymatic degradation by aminopeptidase N and the intact intestinal mucosa, identifying a promising new excipient for peroral delivery of peptides. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1907,1914, 2001 [source] Acylated Flavonol Bisdesmosides, Sinocrassosides A3,A7 and B3, with Aminopeptidase N Inhibitory Activity from Sinocrassula indica,CHEMISTRY & BIODIVERSITY, Issue 3 2009Toshio Morikawa Abstract Six new acylated flavonol bisdesmosides, sinocrassosides A3, A4, A5, A6, A7, and B3 (1,6, resp.), were isolated from the MeOH extract of the whole plant of Sinocrassula indica. The structures of 1,6 were elucidated on the basis of chemical and physicochemical evidence. Among them, 2 and 6 which have an acyl group in the 3,,,-position were found to show strong inhibitory effects on aminopeptidase N activity, which were stronger than that of curcumin. [source] | ||||||||||