CATALYSIS BY ZYMOGENS - INCREASED REACTIVITY AT HIGH IONIC-STRENGTH
CATALYSIS BY ZYMOGENS - INCREASED REACTIVITY AT HIGH IONIC-STRENGTH
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DOI：
10.1016/0014-5793(79)81154-0
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发表时间：
1979-01-01
期刊：
影响因子：
3.5
通讯作者：
NEURATH, H
中科院分区：
文献类型：
--
作者：
LONDSDALEECCLES, JD;KERR, MA;NEURATH, H
Kinetic analysis of the intrinsic activity of trypsinogen and chymotrypsinogen has shown that a major cause for the diminished activity of these zymogens, as compared to the corresponding enzymes, is a deformation of the primary binding site [l-6]. The binding of inhibitors by trypsinogen is-104-times less effective than by trypsin [2] while the maximum velocity of catalysis is only 1 02-times lower [6]. Attempts to increase the intrinsic catalytic activity of these zymogens without proteolytic activation have met with limited success. The addition of dipeptides corresponding to the amino-terminus of trypsin resulted in conformational changes of the p-guanidinobenzoyl derivative of trypsinogen similar to that obtained by tryptic activation [7, 8]. However, this change requires the presence of the guanidinobenzoyl moiety and hence does not manifest itself directly as an increase in the catalytic activity of the zymogen ([7] and JDL-E., unpublished observations). On the other hand the oxidation of Met-192 [3] results in a small but significant increase in the intrinsic activity of chymotrypsinogen by improving the binding of the substrate to the zymogen. In thisAbbreviations: Boc-AlaXlNp, tertiary butyloxycarbonyl alaninep-nitrophenyl ester; NPGB, p-nitrophenyl, p’-guanidinobenzoate; DMF, dimethylformamide; Hepes, 4-(2-hydroxyethyl)-I-piperazme-ethanesulphonic acid; Pipes, piperazine-N-N’-bis (2ethanesulphonic acid)
