標(biāo)記肽Dansyl-Gly-Cys-Val-Leu-Ser-OH
描 述：Fluorogenic substrate for farnesyl diphosphate farnesyltransferase (FTase). The pentapeptide is based on the C-terminal region of H-Ras with a dansyl group attached to the N-terminus. Due to farnesylation of the cysteine thiol group the dansyl group is placed from a polar to a non-polar molecular environment which is accompanied by an enhancement of fluorescence and a shift to a lower wavelength emission maximum of the dansyl group. Complete conversion of the product results in a decrease of the emission maximum wavelength from 565 nm to 515 nm together with a 13-fold enhancement in fluorescence intensity at 505 nm. Dansyl-GCVLS can be used for continuously monitoring FTase activity in the presence of farnesyl diphosphate (FPP) at 505 nm using an excitation wavelength of 340 nm (kcat = 0.5 s⁻¹; Km = 1.4 µM). It represents a useful tool for screening potential FTase inhibitors. The substrate is highly specific to FTase and is not recognized by geranylgeranyl transferse type I (GGTase I). Concentrations of stock solutions of Dns-GCVLS can be calculated from the extinction coefficient of the dansyl moiety (ε₃₄₀ = 4250 M⁻¹cm⁻¹ in 20 mM Tris-HCl, pH 7.5, 10 mM EDTA).
法尼基二磷酸法尼基轉(zhuǎn)移酶(FTase)的熒光底物。該五肽基于H-Ras的c端區(qū)域，并在n端連接一個丹酚基團(tuán)。由于半胱氨酸巰基的法�；�，丹酚基被置于從極性到非極性的分子環(huán)境中，這伴隨著熒光的增強和丹酚基的較低波長發(fā)射最大值的轉(zhuǎn)移。該產(chǎn)物的完全轉(zhuǎn)換導(dǎo)致最大發(fā)射波長從565 nm減少到515 nm，同時在505 nm處熒光強度增強13倍。danyl - gcvls可以在505 nm處連續(xù)監(jiān)測法尼酯二磷酸(FPP)存在時的FTase活性，激發(fā)波長為340 nm (kcat = 0.5 s⁻¹;Km = 1.4µM)。它是篩選潛在的FTase抑制劑的有用工具。Dns-GCVLS的原液濃度可以通過丹酰部分的消光系數(shù)(ε₃₄₀= 4250 M⁻¹cm⁻in 20 mM Tris-HCl, pH 7.5, 10 mM EDTA)計算出來。
