Synthesis and characterization of novel fluorogenic substrates of coagulation factor XIII-A
作者:Kornelia Hardes、M. Zouhir Hammamy、Torsten Steinmetzer
DOI:10.1016/j.ab.2013.07.043
日期:2013.11
Further development of our recently published Glu(pNA)-containing peptides (Anal. Biochem. 428 (2012) 73-80) provided new fluorogenic substrates for the activated blood coagulation factor XIII. A first series was designed by incorporation of Glu(AMC) at the penultimate position from the N terminus. For the best derivative H-Tyr-Glu(AMC)-Val-Lys-Val-Ile-NH2, a moderate k(cat)/K-m value of 34 s(-1) M-1 was determined, which is more than 100-fold reduced compared with the previously reported Glu(pNA) substrates. Furthermore, two fluorescence resonance energy transfer (FRET) substrates Were prepared by incorporation of an N-methyl-anthraniloyl fluorophore and a 2,4-dinitrophenyl quencher. Both substrates were excellently cleaved by FXIII-A(2)*, which is generated from its zymogen by activation of thrombin in the presence of calcium ions. In the absence and presence of H-Gly-ethyl ester, k(cat)/K-m values of 8010 and 8660 s(-1) M-1, respectively, were found for the conversion of H-Lys(N(Me)Abz)-Glu(NH-(CH2)(4)-NH-Dnp)-Val-Lys-Val-Ile-Gly-NH2 (substrate 8). These values are more than 200-fold improved compared with the Glu(AMC) substrates. Substrate 8 is suitable for the measurement of FXIII-A2* activities in plasma samples as well as for in vitro measurements. Furthermore, it was used for the determination of the inhibitory potency of a newly synthesized chloromethyl ketone derivative, Cbz-Phe-Glu(CMK)-Val-Lys-Val-Ile-Gly-NH2, which was found to be a potent irreversible inhibitor of FXIII-A2*. (C) 2013 Elsevier Inc. All rights reserved.