Substituents effects on activity of kynureninase from Homo sapiens and Pseudomonas fluorescens
作者:Chandan Maitrani、Robert S. Phillips
DOI:10.1016/j.bmc.2013.05.039
日期:2013.8
5-chloro-l, 3,5-dibromo-l and 5-bromo-3-chloro-dl) have been synthesized and tested for their substrate activity with human and Pseudomonas fluorescens kynureninase. All of the substituted kynurenines examined have substrate activity with both human as well as P. fluorescens kynureninase. For the human enzyme, 3- and 5-substituted kynurenines have kcat and kcat/Km values higher than l-kynurenine, but less
一系列取代的犬尿氨酸的(3-溴- DL,3-氯DL,3-氟- DL,3-甲基DL,5-溴升,5-氯升,3,5-二溴升和已经合成了5-溴-3-氯-dl),并用人和荧光假单胞菌kynureninase检测了它们的底物活性。检查的所有取代的犬尿氨酸都具有人和荧光假单胞菌犬尿氨酸酶的底物活性。对于人类酶,3-和5取代的犬尿氨酸具有k cat和k cat / K m值高于1- kynurenine,但低于生理底物3-hydroxykynurenine。然而,3,5-二溴-和5-溴-3-氯炔尿氨酸的k cat和k cat / K m值与人炔尿苷酶的3-羟基犬尿氨酸接近。3-卤代取代基对与人犬尿氨酸酶的反应性的影响可能归因于电子效应和/或卤素键。相比之下,对于细菌酶,3-甲基,3-卤代和3,5-二卤代尿嘧啶是较差的底物,而3-氟,5-溴和5-氯炔尿氨酸具有k cat和k cat / K m其生理底物1-
Differential effects of bromination on substrates and inhibitors of kynureninase from Pseudomonas fluorescens
作者:Christian Heiss、Jay Anderson、Robert S. Phillips
DOI:10.1039/b208910f
日期:2003.1.13
inhibitors of kynureninasefromPseudomonas fluorescens. Both 3-bromo-L-kynurenine and 5-bromo-L-kynurenine were found to be substrates with similar k(cat) values to L-kynurenine, but the K(m) value for 3-bromo-L-kynurenine is very high (ca. 2 mM) compared to that for 5-bromo-L-kynurenine (11 microM) and L-kynurenine (25 microM). Both isomers of bromokynurenine react with kynureninase within the dead