Substrate-based peptidomimetic inhibitors of the Murray Valley encephalitis virus NS2B/NS3 serine protease: A P1–P4 SAR study
摘要:
Murray Valley encephalitis is an infectious disease spread by a mosquito-borne virus endemic in Papua New Guinea and northern Australia. In the past decade, it has spread to various regions of Australia and there is currently no therapeutic treatment against this disease. An attractive drug target is the viral serine protease NS2B/NS3, a critical enzyme involved in viral replication. Herein, we report the inhibitory activities of 37 C-terminal agmatine peptidomimetic inhibitors which led to the design of a novel structurally-constrained competitive inhibitor 38 possessing a K-i of 2.5 +/- 0.5 mu M. We believe our data provides crucial insights into the viral protease active site specificity which could be used to facilitate drug design against Murray Valley encephalitis viral infections. (C) 2013 Elsevier Masson SAS. All rights reserved.
N-Carbamoylputrescine, a citrulline-derived polyamine, is not a significant citrulline metabolite in rats
摘要:
Citrulline, a key amino acid of the urea cycle, has been shown to play a regulatory role in protein and energy metabolism in mammals. We questioned whether N-carbamoyl-putrescine (NCP), the decarboxylated derivative of citrulline, could play a role in the biological properties of this amino acid. To evidence the presence of NCP in mammalian tissues, we developed a sensitive reverse-phase high-performance liquid chromatography (HPLC) with fluorimetric detection method with precolumn dansyl derivatization and solid-phase extraction for the determination of NCP together with polyamines in biological samples. Dansyl NCP was identified with a 5.85-min retention time. Linearity was obtained in a concentration range of 0.125 to 12.5 mu M. Intraday and day-to-day relative coefficients of variation ranged from 8.9% to 12.3% and from 14% to 14.3%, respectively. Recovery rates in serum ranged from 75% to 83%. Thereafter, we used this method to search for the presence of NCP in serum, muscle, liver, jejunum, and ileum in rats after both short-term intraperitoneal injection and long-term oral citrulline supplementation. We failed to detect NCP in these animals. These data suggest that NCP is not a significant citrulline metabolite in rats. (C) 2012 Elsevier Inc. All rights reserved.