caa a22 4500 378855999 CHVBK 20180305123335.0 cr unu---uuuuu 161128e20031225xx s 000 0 eng 10.1515/BC.2003.178 doi (NATIONALLICENCE)gruyter-10.1515/BC.2003.178 Potent Bivalent Inhibition of Human Tryptase-? by a Synthetic Inhibitor [Elektronische Daten] [T. Selwood, K.C. Elrod, N. M. Schechter] Human tryptase-? (HT?) is a unique serine protease exhibiting a frame-like tetramer structure with four active sites directed toward a central pore. Potent inhibition of HT? has been attained using CRA-2059. This compound has two phenylguanidinium head groups connected via a linker capable of spanning between two active sites. The properties of the CRA-2059:HT? interaction were defined in this study. Tightbinding reversible inhibition was observed with an inhibition constant (Ki) of 620 pM, an association rate constant of 7×07 M -1s-1 and a relatively slow dissociation rate constant of 0.04 s-1. Bivalent inhibition was demonstrated by displacement of paminobenzamidine from the primary specificity pocket with a stoichiometry, [CRA-2059]0/[HT?]0, of 0.5. The potency of the bivalent interaction was illustrated by CRA-2059 inhibition of HT?, 24% or 53% inhibited by preincubation with an irreversible inhibitor. Two interactions were observed consistent with mono and bivalent binding; the Ki value for bivalent inhibition was at least 104-fold lower than that for monovalent inhibition. Comparison of the affinities of CRA-2059 and phenylguanidine for HT? finds an approximate doubling of the free energy change upon bivalent binding. This doubling suggests that the linker portion minimally hinders the binding of CRA-2059 to HT?. The potency of CRA-2059 is thus attributable to effective bivalent binding. Copyright © 2003 by Walter de Gruyter GmbH & Co. KG Biochemistry nationallicence Molecular biology nationallicence Cellular biology nationallicence Selwood T. aut Elrod K.C. aut Schechter N. M. aut Biological Chemistry Walter de Gruyter 384/12(2003-12-25), 1605-1611 1431-6730 384:12<1605 2003 384 bchm https://doi.org/10.1515/BC.2003.178 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/BC.2003.178 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Selwood T. aut NATIONALLICENCE 700 1- Elrod K.C. aut NATIONALLICENCE 700 1- Schechter N. M. aut NATIONALLICENCE 773 0- Biological Chemistry Walter de Gruyter 384/12(2003-12-25), 1605-1611 1431-6730 384:12<1605 2003 384 bchm CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter