title: Aleppo tannin: structural analysis and salivary amylase inhibition.
abstract: The effectiveness and specificity of a tannin inhibition on human salivary amylase (HSA) catalyzed hydrolysis was studied using 2-chloro-4-nitrophenyl 4-O-beta-D-galactopyranosyl-alpha-maltoside (GalG(2)-CNP) and amylose substrates. Aleppo tannin was isolated from the gall nut of Aleppo oak. This tannin is a gallotannin, in which glucose is esterified with gallic acids. This is the first kinetic report, which details the inhibitory effects of this compound on HSA. A mixed non-competitive type inhibition has been observed on both substrates. The extent of inhibition is markedly dependent on the substrate-type. Kinetic constants were calculated from Lineweaver-Burk secondary plots for GalG(2)-CNP (K(EI) 0.82 microg mL(-1), K(ESI) 3.3 microg mL(-1)). This indicates a 1:1 binding ratio of inhibitor-enzyme and/or inhibitor-enzyme-substrate complex. When amylose was the substrate the binding ratio of inhibitor to enzyme-substrate complex was found to be 2:1, with the binding constants of K(EI) 17.4 microg mL(-1), K(ESI) 14.9 microg mL(-1), K(ESI(2)) 9.6 microg mL(-1). Presumably, the tannin inhibitor can bind not only to HSA, but to the amylose substrate, as well. Kinetic data suggest that Aleppo tannin is a more efficient amylase inhibitor than the recently studied other tannin with quinic acid core (GalG(2)-CNP: K(EI) 9.0 microg mL(-1), K(ESI) 47.9 microg mL(-1)).
authors.affiliation: University of Debrecen, Faculty of Sciences, Department of Biochemistry, PO Box 55, H-4010 Debrecen, Hungary.
authors.forename: Agnes
authors.initials: A
authors.lastname: Zajácz
authors.forename: Gyöngyi
authors.initials: G
authors.lastname: Gyémánt
authors.forename: Natale
authors.initials: N
authors.lastname: Vittori
authors.forename: Lili
authors.initials: L
authors.lastname: Kandra
mesh_terms: D000681:Amylases / Q000378:metabolism*; D000688:Amylose / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D002240:Carbohydrate Sequence; D004791:Enzyme Inhibitors / Q000737:chemistry*; D005960:Glucosides / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D047348:Hydrolyzable Tannins / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D009754:Nuts / Q000737:chemistry; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D029963:Quercus / Q000737:chemistry; D011801:Quinic Acid / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D013634:Tannins / Q000737:chemistry* / Q000378:metabolism
chemical_list: C411063:2-chloro-4-nitrophenyl-4-O-galactopyranosylmaltoside; D004791:Enzyme Inhibitors; D005960:Glucosides; D047348:Hydrolyzable Tannins; D009844:Oligosaccharides; D013634:Tannins; C519396:aleppo tannin; D011801:Quinic Acid; D000688:Amylose; D000681:Amylases