Glycosides Having Chromophores as Substrates for Sensitive Enzyme Analysis. V. Synthesis of 6'-O-Substituted 2',7'-Dichlorofluorescein N-Acetyl-.BETA.-D-glucosaminides as Substrates for the Rate-Assay of N-Acetyl-.BETA.-D-glucosaminidase.
作者:Kouichi KASAI、Kiyoshi OKADA、Nobuyuki YAMAJI
DOI:10.1248/cpb.41.1513
日期:——
Sixteen novel 6'-O-substituted 2', 7'-dichlorofluorescein N-acetyl-β-D-glucosaminides (2a-p) were synthesized from 2', 7'-dichlorofluorescein 2, 3, 4, 6-tetraacetyl-β-D-glucosaminide (10), prepared through 3 steps from 2', 7'-dichlorofluorescein (3). These N-acetyl-β-D-glucosaminides were examined to evaluate their solubility under the weakly acidic rate-assay conditions (pH 5.0) and their kinetic parameters with N-acetyl-β-D-glucosaminidase. Among these compounds, 6'-O-carboxymethyl- (2a), 6'-O-(N, N-dimethylaminoethyl)- (2i), and 6'-O-sulfoxyethyl-2', 7'-dichlorofluorescein N-acetyl-β-D-glucosaminides (2p), are considered to be potential chromogenic substrates for the rate-assay of N-acetyl-β-D-glucosaminidase, since they showed good solubility of more than 10mM, moderate Km values of 1.46-2.04mM, and higher sensitivity to the enzyme than 2-chloro-4-nitrophenyl-N-acetyl-β-D-glucosaminide.
研究人员从 2',7'-二氯荧光素 (3) 经过 3 个步骤制备的 2',7'-二氯荧光素 2,3,4,6-四乙酰基-β-D-氨基葡萄糖苷 (10) 合成了 16 种新型 6'-O 取代的 2',7'-二氯荧光素 N-乙酰基-β-D-氨基葡萄糖苷 (2a-p)。研究人员考察了这些 N-乙酰基-β-D-氨基葡萄糖苷在弱酸性速率测定条件(pH 值为 5.0)下的溶解度,以及它们与 N-乙酰基-β-D-氨基葡萄糖苷酶的动力学参数。在这些化合物中,6'-O-羧甲基-(2a)、6'-O-(N,N-二甲基氨基乙基)-(2i)和 6'-O-硫氧乙基-2',7'-二氯荧光素 N-乙酰基-β-D-氨基葡萄糖苷(2p)、被认为是 N-乙酰基-β-D-葡糖胺苷酶速率测定的潜在发色底物,因为它们具有良好的溶解性(超过 10mM)、适中的 Km 值(1.与 2-氯-4-硝基苯基-N-乙酰基-β-D-葡糖胺苷相比,它们的溶解度好,超过 10mM,Km 值在 1.46-2.04mM 之间,对酶的敏感性更高。