Inhibitory effects of tannin on human salivary alpha-amylase.
Here, we first report on the effectiveness and specificity of tannin inhibition of 2-chloro-4-nitrophenyl-4-O-beta-d-galactopyranosylmaltoside hydrolysis that is catalyzed by human salivary alpha-amylase (HSA). Tannin was gallotannin in which quinic acid was esterified with 2-7 units of gallic acid. A number of studies establish that polyphenols-like tannins-may prevent oral diseases, e.g., dental caries. Kinetic analyses confirmed that the inhibition of hydrolysis is a mixed non-competitive type and only one molecule of tannin binds to the active site or the secondary site of the enzyme. Since Dixon plots were linear, product formation could be excluded from the enzyme-substrate-inhibitor complex (ESI). Kinetic constants calculated from secondary plots and non-linear regression are almost identical, thereby confirming the suggested model. Kinetic constants (K(EI) = 9.03 microgmL(-1), K(ESI) = 47.84 microgmL(-1)) show that tannin is as an effective inhibitor of HSA as acarbose and indicate a higher stability for the enzyme-inhibitor complex than ESI.
Kandra
Lili
L
Institute of Biochemistry, Faculty of Sciences, University of Debrecen, H-4010 Debrecen, P.O. Box 55, Hungary. kandra@tigris.unideb.hu
Gyémánt
Gyöngyi
G
Zajácz
Agnes
A
Batta
Gyula
G
D000893:Anti-Inflammatory Agents / Q000378:metabolism*; D001252:Astringents / Q000737:chemistry / Q000493:pharmacokinetics*; D001665:Binding Sites; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D003731:Dental Caries; D004795:Enzyme Stability; D006801:Humans; D047348:Hydrolyzable Tannins / Q000737:chemistry / Q000493:pharmacokinetics*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000516:alpha-Amylases / Q000037:antagonists & inhibitors* / Q000378:metabolism*
C093675:2-chloro-4-nitrophenyl 4(4)-galactopyranosylmaltotetraoside; D000893:Anti-Inflammatory Agents; D001252:Astringents; D047348:Hydrolyzable Tannins; D009844:Oligosaccharides; D000516:alpha-Amylases