Proteases synthetic

An example of a direct spectrophotometrical assay is the use of synthetic peptide -nitroanilide substrates to determine protease activity. The /)-nitroani1ine group Hberated from the substrates by the protease can be determined spectrophotometricaHy at 410 nm. An example of an indirect (coupled) spectrophotometric assay is the determination of a-amylase using -nitrophenyLmaltoheptaoside. Initially, the substrate is cleaved by the a-amylase and subsequentiy one of the reaction products, -nitrophenyLmaltotrioside, is cleaved by a-glucosidase, hberating -nitrophenyl, a chromophore... 

The pH dependence of HIV-1 protease has been assessed by measuring the apparent inhibition constant for a synthetic substrate analog (b). The data are consistent with the catalytic involvement of ionizable groups with pK values of 3.3 and 5.3. Maximal enzymatic activity occurs in the pH range between these two values. On the basis of the accumulated kinetic and structural data on HIV-1 protease, these pK values have been ascribed to the... 

In vitro and ex vivo studies have shown that FATPs transport LCFAs and very long-chain fatty acids (VLCFAs) but no medium-chain fatty acids, fatty acid esters, or lipid-soluble vitamins [4]. LCFA transport is inhibited by prior protease treatment. Synthetic substrates for FATPs include 14C-labeled fatty acids and the fluorescently labeled fatty acid analogue C1 -BODEP Y-Cl 2. Using the latter substrate, differences in fatty acid uptake kinetics between FATP expressing 3T3 LI adipocytes and 3T3 LI fibroblasts, which are devoid of FATPs, can be readily appreciated (Fig. 2). 

Pal, G., Santamaria, F., Kossiakoff, A.A., and Lu, W. (2003) The first semi-synthetic serine protease made by native chemical ligation. Protein Expr. Purif. 29(2), 185-192. 

L. Selk, S. B. Kent, and A. Wlodawer, Structure of complex of synthetic HIV-1 protease with a substrate-based inhibitor at 2.3 A resolution, Science 246 1149 (1989). 

Selk, L. Clawson, J. Schneider, and S. Kent, Conserved folding in retroviral Protease Crystal structure of a synthetic HIV-1 protease, Science 245 616 (1989). 

X-ray crystallographic structure of a complex between a synthetic protease of human immunodeficiency virus 1 and a substrate based hydroxyethyl-amine inhibitor, Proc. Natl. Acad. Sci. 87 8805 (1990). 

Chabry,J., Caughey, B., and Chesebro, B. (1998). Specific inhibition of in vitro formation of protease-resistant prion protein by synthetic peptides. /. Biol. Chem. 273, 13203-13207. 

M Schnolzer, SBH Kent. Constructing proteins by dovetailing unprotected synthetic peptides backbone-engineered HIV protease. Science 256, 221, 1992. 

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