Protease selectivities

Katz, B. A. Finer-Moore, J. Mortezaei, R. Rich, D. H. Stroud, R. M. Episelection Novel K. approximately nanomolar inhibitors of serine proteases selected by binding or chemistry on an enzyme surface. Biochemistry 1995, 34, 8264-8280. 

DPP IV/CD26 (DPP IV), a cell-surface protease, selectively removes an A/-termi-nal dipeptide from peptides with proline or alanine in the second position. DPP IV... 

Protein G. This vitamin K-dependent glycoproteia serine protease zymogen is produced ia the Hver. It is an anticoagulant with species specificity (19—21). Proteia C is activated to Proteia by thrombomodulin, a proteia that resides on the surface of endothefial cells, plus thrombin ia the presence of calcium. In its active form, Proteia selectively iaactivates, by proteolytic degradation. Factors V, Va, VIII, and Villa. In this reaction the efficiency of Proteia is enhanced by complex formation with free Proteia S. la additioa, Proteia activates tissue plasminogen activator, which... 

Optically Active Acids and Esters. Enantioselective hydrolysis of esters of simple alcohols is a common method for the production of pure enantiomers of esters or the corresponding acids. Several representative examples are summarized ia Table 4. Lipases, esterases, and proteases accept a wide variety of esters and convert them to the corresponding acids, often ia a highly enantioselective manner. For example, the hydrolysis of (R)-methyl hydratropate [34083-55-1] (40) catalyzed by Hpase P from Amano results ia the corresponding acid ia 50% yield and 95% ee (56). Various substituents on the a-carbon (41—44) are readily tolerated by both Upases and proteases without reduction ia selectivity (57—60). The enantioselectivity of many Upases is not significantly affected by changes ia the alcohol component. As a result, activated esters may be used as a means of enhancing the reaction rate. 

A number of steroids have been regioselectively acylated ia a similar manner (99,104). Chromobactenum viscosum hpase esterifies 5a-androstane-3P,17P-diol [571-20-0] (75) with 2,2,2-triduoroethyl butyrate ia acetone with high selectivity. The hpase acylates exclusively the hydroxy group ia the 3-position giving the 3P-(monobutyryl ester) of (75) ia 83% yield. In contrast, bacillus subtilis protease (subtihsia) displays a marked preference for the C-17 hydroxyl. Candida iylindracea]i 2Lse (CCL) suspended ia anhydrous benzene regioselectively acylates the 3a-hydroxyl group of several bile acid derivatives (104). 

Inhibition of inflammatory cytokines (Fig. 2) Humanized monoclonal anti-TNF antibodies (Infliximab (Remicade ), Adalimumab (Humira )) bind with high selectivity to human TNF-a and neutralize its activity. Thereby, infliximab decreases the effects of enhanced TNF levels during inflammatory disease such as production of proteases, chemokines, adhesion molecules, cyclooxygenase products (prostaglandins), and proinflammatory molecules such as interleukin-1 and -6. The antibodies may also recognize membrane-bound TNF-a on lymphocytes and other immune cells. These cells may subsequently become apoptotic or are eliminated via Fc-receptor-mediated phagocytosis. 

ET-1 from big-ET-1 by other proteases such as neutral endopeptidase or other currently unidentified proteases. Therefore, dual inhibition of ECE and NEP might inhibit ET-l generation more efficiently, than that seen for selective ECE inhibitors. However, dual inhibiton of ECE and NEP could also increase the risk for the development of AD, as both enzyme classes are involved in the degradation of A 3 peptide. 

Tetanus is a disease caused by the release of neurotoxins from the anaerobic, spore-forming rod Clostridium tetani. The clostridial protein, tetanus toxin, possesses a protease activity which selectively degrades the pre-synaptic vesicle protein synaptobrevin, resulting in a block of glycine and y-aminobutyric acid (GABA) release from presynaptic terminals. Consistent with the loss of neurogenic motor inhibition, symptoms of tetanus include muscular rigidity and hyperreflexia. The clinical course is characterized by increased muscle tone and spasms, which first affect the masseter muscle and the muscles of the throat, neck and shoulders. Death occurs by respiratory failure or heart failure. 

Inhibitors for proteases plasmepsin I and II of the malaria parasite Plasmodium falciparum, with a good plasmepsin/human protease cathepsin D selectivity, have been identified via library construction involving rapid microwave-accelerated Suzuki reactions [57]. The phenyl ring of the biphenyl unit in the lead compound M-((lS)-l- [((lS,2S)-3- [(lS)-2-amino-l-(4-phenyl-benzyl)-2-oxoethyl]amino -2-hydroxy-l-phenoxypropyl)amino]carbonyl -2-methylpropyl)pyridine-2-carboxamide has been altered by performing Suzuki reactions on N-((lS)-l- [((lS,2S)-3- [(lS)-2-amino-l-(4-bromobenzyl)-2-oxoethyl]amino -2-hydroxy-l-phenoxypropyl)amino]carbonyl -2-methyl-propyl)pyridine-2-carboxamide (Scheme 37). In particular, a 2-benzofuryl moiety proved to be interesting since a Ki value of 13 nM for plasmepsin I and... 

In a first report [24], the enantioselectivities of various proteases were evaluated by comparing the biocatalyzedhydrolysis of2-chloroethyl esters of N-acetyl-i- and D-amino acids in water and their transesterification with w-propanol in butyl ether. By comparing the ratio of the kc t/Ku values for the l- and D-enantiomers in the two reactions, a remarkable relation of the proteases enantioselectivity was observed apparently, in this case, the organic solvents destroyed the selectivity of the tested enzymes. This finding... 

Of course, the influence of organic solvents on enzyme enantioselectivity is not limited to proteases but it is a general phenomenon. Quite soon, different research groups described the results obtained with lipases [28]. For instance, the resolution of the mucolytic drug ( )-trans-sobrerol (11) was achieved by transesteriflcation with vinyl acetate catalyzed by the lipase from Pseudomonas cepacia adsorbed on celite in various solvents. As depicted in Scheme 1.3 and Table 1.5, it was found that t-amyl alcohol was the solvent of choice in this medium, the selectivity was so high ( >500) that the reaction stopped spontaneously at 50% conversion giving both +)4rans-sobrerol and (—)-trans-sobrerol monoacetate in 100% optical purity [29]. 

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