42808-06-0Relevant articles and documents
A new chiral ligand exchange capillary electrophoresis system based on Zn(ii)-l-leucine complexes coordinating with β-cyclodextrin and its application in screening tyrosinase inhibitors
Su, Yuan,Mu, Xiaoyu,Qi, Li
, p. 55280 - 55285 (2015/02/05)
Tyrosinase plays a key role in melanin formation, and it is closely related to hyper pigmentation in animals and enzymatic browning in food. Thus, it is of great significance to screen inhibitors of tyrosinase. In this work, a new chiral ligand exchange-capillary electrophoresis (CLE-CE) system based on the coordination effect of Zn(ii)-l-leucine complexes and β-cyclodextrin (β-CD) was developed for screening the inhibitors of tyrosinase. The effects of the concentration of β-CD, buffer pH, the ratio of l-leucine to Zn(ii), and the complex concentration were investigated with Dns-d,l-tyrosine, Dns-d,l-valine and Dns-d,l-phenylalanine as the tested analytes. The optimum buffer conditions were composed of 100.0 mM boric acid, 5.0 mM ammonium acetate, 3.0 mM Zn(ii), 6.0 mM l-leucine and 4.0 mM β-CD at pH 8.2. It has been found that six pairs of Dns-d,l-AAs could be baseline-separated and five pairs of Dns-d,l-AAs were partly enantioseparated. Then the quantitative analysis of l-tyrosine was conducted and good linearity (r2 = 0.992) was obtained with a concentration ranging from 12.95 μM to 413.3 μM. A kinetics study of tyrosinase was realized, and the Km and Vmax were 636 μM and 312 μmol min-1 mg-1. Moreover, the proposed method was applied in screening the inhibitors of tyrosinase with four kinds of chalcones as the model inhibitors. The results demonstrated that the developed CLE-CE system was favorable for screening enzyme inhibitors, and showed great potential in related drugs discovery and clinical analysis in the future.
Mimics of Transaminase Enzymes
Breslow, R.,Czarnik, A. W.,Lauer, M.,Leppkes, R.,Winkler, J.,Zimmerman, S.
, p. 1969 - 1979 (2007/10/02)
Pyridoxamine has been attached to the primary side and to the secondary side of β-cyclodextrin; the resulting compounds convert α-keto acids to amino acids with substrate selectivity and some stereoselectivity.Pyridoxamine has also been attached to a synthetic macrocycle; the attached binding group showed substrate selectivity.Chains carrying catalytic basic groups have been attached to pyridoxamine; appropriate systems catalyze the prototropic rearrangement characteristic of transamination.A catalyzed HCl elimination involving chloropyruvic acid was observed.A tetrahydroquinoline system related to pyridoxamine was synthesized to permit the stereochemically defined placement of a basis catalytic group.This converted keto acids to amino acids with good stereoselectivity for the formation of optically active products.