Peptide leukocyte elastase

Figure 15.6 Chromatogram of a plasma standard of human leukocyte elastase inhibitors obtained by using LC-LC. Adapted from Journal of Liquid Chromatography and Related Technologies, 19, R. A. Earley and L. R Tini, Versatile multidimensional chromatographic system for di ug discovery as exemplified by the analysis of a non-peptidic inhibitor of human leukocyte elastase , pp. 2527-2540, 1996, by courtesy of Marcel DekkeiTnc.

This approach has been mainly applied to peptide-based inhibitors of proteases, where the inhibitory molecule is a peptide with a transition state isostere appended to it, and the cognate substrate is simply a peptide of the same amino acid sequence, but lacking the isostere functionality. Examples where good correlations between the free energy of inhibitor binding and the free energy of kcJKM have been found, include peptide-trifluoromethyl ketone inhibitors of human leukocyte elastase (Stein et al., 1987) and peptide-phosphonamidate inhibitors of the metalloprotease ther-molysin (Bartlett and Marlowe, 1983). 

FR901277 - cyclic peptide that inhibits human leukocyte elastase... 

Powers, J. C., et al. 1977. Specificity of porcine pancreatic elastase, human leukocyte elastase and cathepsin G. Inhibition with peptide chloromethyl ketones. Biochim Biophys Acta 485 156. 

M. Iierach. Isolation and characteriatelon of native and recombinant eglin c from EL eoii, selective proteinase inhibitors far hnman leukocyte elastase, cathepain G and chymotrypsiiL Peptides Structure and Function (C. M. Debs, V. J. Hraby, and K. D. Kopple, edsj. Pierce Chemical, Rockford, Illinois, 1985,p385. 

The reactive site of i-PI has a Ala-Ile-Pro-Met Ser-Ile-Pro-Pro sequence where the asterisk indicates the bond cleaved when i-PI pro-tase complexes are dissociated at high pH or by using nucleophiles. We have synthesized a number of peptides with the amino acid sequence at the ai-PI reactive site and have shown them to be perfectly adequate substrates for human leukocyte elastase. However, oxidation of the methionine residue of the substrates to a methionine sulfoxide residue (see Table III) almost completely destroys their reactivity toward human leukocyte elastase and other proteases (8,9). Oxidation of ai-PI itself destroys its ability to inhibit most proteases (10). 

Table III. Hydrolysis of Peptide Substrates by Human Leukocyte Elastase...

Peptide chloromethyl ketone inhibitors have been developed for almost every serine protease that has been characterized adequately (30). For example, human leukocyte elastase, due to its involvement in emphysema, has been studied extensively with this class of inhibitor (32). The rate at which peptide chloromethyl ketones inhibit elastase is influenced by their interaction with the primary substrate binding site (Si) of the enzyme and by interactions at other subsites. The most effective chloromethyl ketone elastase inhibitor found thus far is MeO-Suc-Ala-Ala-Pro-ValCH2Cl (MeO-Suc- = CH3OCOCH2CH2CO-). This will not inhibit the other major leukocyte protease, cathepsin G (see Table VI). In contrast, Z-Gly-Leu-Phe-CH2C1 (Z = C6H5CH2OCO-) inhibits cathepsin G, but not elastase. Both enzymes can be inhibited with Ac-Ala-Ala-Pr o-V alCH2Cl. 

Stein, R.L. and Strimpler, A.M. 1987. Catalysis by human leukocyte elastase aminolysis of acyl enzymes by amino acid amides and peptides. Biochemistry, 26, 2238-2242. 

Warner, P., Green, R. C., Gomes, B. and Strimpler, A. M. (1994) Non-peptidic inhibitors of human leukocyte elastase. 1. The design and synthesis of pyridone-containing inhibitors. J. Med. Chem., 37, 3090-3099. 

K. Nakajima, J. C. Powers, B. M. Ashe, and M. Zimmerman. Mapping the extended substrate binding site of cathepsin G and human leukocyte elastase. Studies with peptide substrates related to the alpha 1-protease inhibitor reactive site. J. Biol. Chem. 254 4027 (1979). 

Non-Peptidic Inhibitors of Human Leukocyte Elastase. 1. The Design and Synthesis of Pyridone-Containing Inhibitors. 

S. Feeney, B. C. Gomes, B. J. Kosmider, G. B. Steelman, R. M. Thomas, E. P. Vacek, J. C. Williams, D. J, Wolanin, and S. A. Woolson, ]. Med. Chem., 38, 98 (1995). Non-Peptidic Inhibitors of Human Leukocyte Elastase. 5. Design, Synthesis, and X-Ray Crystallography of a Series of Orally Active 5-Aminopyrimidin-6-one-Containing Trifluoromethyl Ketones. 

Two representative procedures are presented in detail. The first, preparation of Z-Gly-Leu-PheCH-Cl, involves deblocking of Z-PheCH-Cl and subsequent coupling of the deblocked chloromethyl ketone with Z-Gly-Leu-OH. This compound is an excellent inhibitor of chymotryp-sin and cathepsin G. The second procedure, that for Ac-Ala-Ala-Pro- ValCH-Cl, illustrates the synthesis of a peptide chloromethyl ketone from Boc-Val-OH with a minimum of isolation and purification along the way this compound is an excellent inhibitor of porcine pancreatic and human leukocyte elastase. ... 

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