Amour A, Reboud-Ravaux M, de Rosny E, Abouabdellah A, Bégue J P, Bonnet-Delpon D, Le Gall M
Département de Biologie Cellulaire et Supramoléculaire, Institut Jacques Monod, Université Paris VII, France.
J Pharm Pharmacol. 1998 Jun;50(6):593-600. doi: 10.1111/j.2042-7158.1998.tb06892.x.
New fluorinated inhibitors have been designed to target two major proteases-human leucocyte elastase and HIV-1 protease. Two series of beta-peptidyl trifluoromethyl alcohols (TFMAs) Z-L-Val-NH-*CH(Y)*CH(OH)-CF3, where *C is the chiral centre, varied in the nature of the substituent Y, a phenylethyl [-(CH2)2-C6H5] or an isopropyl [-CH(CH3)2] group. These TFMAs were first synthesized as two pairs of the syn and anti diastereoisomers. The inhibitory effects of these mixtures were then assessed on three serine proteases chosen on the basis of the aromatic and aliphatic nature of the substituents-human leucocyte elastase (HLE), human cathepsin G (HCG) and porcine pancreatic elastase (PPE). In the presence of detectable inhibition, each epimer at C2 was separated to determine its inhibition constant (Ki) towards HLE, HCG and PPE. The stereoisomerically pure TFMAs were then oxidized into peptidyl trifluoromethyl ketones (TFMKs) for similar inhibition assays. The absolute configuration of the compounds remained unknown. One epimer at C2 of each syn and anti TFMA with the phenylethyl substituent behaved as a competitive inhibitor towards HLE and HCG with inhibition constants below the millimolar range, whereas their TFMK counterparts were non-inhibitors. In the second series, the two ketones inhibited both elastases with Ki values in the micromolar range, whereas only the syn TFMA was active towards HLE (Ki = 5.65 x 10(-4)M). The tested compounds also had structural properties compatible with recognition by HIV-1 protease. The inhibition of the enzyme was observed with TFMK only (IC50 = 15-200 microM). The phenylethyl substituent promoted inhibition by a factor of 10 (IC50 = 15 microM) compared with the isopropyl substituent (IC50 = 200 microM) leading to selective inhibition of HIV-1 protease. Isomerically pure TFMKs were more potent towards HLE than the alcohols from which they were obtained. However, an enantiomerically pure TFMA selectively inhibited HLE unlike its TFMK analogue which also inhibited PPE. This last result together with the selective inhibition of HIV-1 protease by TFMK with a phenylethyl substituent might be relevant to the design of specific HLE and HIV-1 inhibitors as therapeutic agents.
新型含氟抑制剂已被设计用于靶向两种主要蛋白酶——人白细胞弹性蛋白酶和HIV-1蛋白酶。设计了两个系列的β-肽基三氟甲基醇（TFMAs）Z-L-缬氨酰-NH-*CH(Y)CH(OH)-CF3，其中C为手性中心，取代基Y的性质不同，为苯乙基[-(CH2)2-C6H5]或异丙基[-CH(CH3)2]基团。这些TFMAs最初被合成为两对顺式和反式非对映异构体。然后根据取代基的芳香族和脂肪族性质选择三种丝氨酸蛋白酶——人白细胞弹性蛋白酶（HLE）、人组织蛋白酶G（HCG）和猪胰弹性蛋白酶（PPE），评估这些混合物的抑制作用。在存在可检测到的抑制作用时，分离C2位的每个差向异构体，以确定其对HLE、HCG和PPE的抑制常数（Ki）。然后将立体异构体纯的TFMAs氧化为肽基三氟甲基酮（TFMKs），进行类似的抑制试验。这些化合物的绝对构型仍然未知。每个带有苯乙基取代基的顺式和反式TFMA的C2位差向异构体之一对HLE和HCG表现为竞争性抑制剂，抑制常数低于毫摩尔范围，而它们的TFMK对应物则无抑制作用。在第二个系列中，两种酮对两种弹性蛋白酶均有抑制作用，Ki值在微摩尔范围内，而只有顺式TFMA对HLE有活性（Ki = 5.65×10(-4)M）。所测试的化合物还具有与HIV-1蛋白酶识别兼容的结构特性。仅观察到TFMK对该酶有抑制作用（IC50 = 15 - 200 microM）。与异丙基取代基（IC50 = 200 microM）相比，苯乙基取代基使抑制作用增强了10倍（IC50 = 15 microM），从而导致对HIV-1蛋白酶的选择性抑制。立体异构体纯的TFMKs对HLE的活性比其来源的醇更强。然而，对映体纯的TFMA选择性抑制HLE，与其TFMK类似物不同，后者也抑制PPE。最后这个结果以及带有苯乙基取代基的TFMK对HIV-1蛋白酶的选择性抑制可能与设计作为治疗剂的特异性HLE和HIV-1抑制剂有关。
