Protease selection, primary

Selected entries from Methods in Enzymology [vol, page(s)] Association constant determination, 259, 444-445 buoyant mass determination, 259, 432-433, 438, 441, 443, 444 cell handling, 259, 436-437 centerpiece selection, 259, 433-434, 436 centrifuge operation, 259, 437-438 concentration distribution, 259, 431 equilibration time, estimation, 259, 438-439 molecular weight calculation, 259, 431-432, 444 nonlinear least-squares analysis of primary data, 259, 449-451 oligomerization state of proteins [determination, 259, 439-441, 443 heterogeneous association, 259, 447-448 reversibility of association, 259, 445-447] optical systems, 259, 434-435 protein denaturants, 259, 439-440 retroviral protease, analysis, 241, 123-124 sample preparation, 259, 435-436 second virial coefficient [determination, 259, 443, 448-449 nonideality contribution, 259, 448-449] sensitivity, 259, 427 stoichiometry of reaction, determination, 259, 444-445 terms and symbols, 259, 429-431 thermodynamic parameter determination, 259, 427, 443-444, 449-451. 

Primary screening interest for the set was the aspartyl protease /3-secretase,51 one of two proteases that cleave the /3-amyloid precursor protein (APP) to produce /3-amyloid peptide (A/3) in the human brain, a key event in the pathogenesis of Alzheimer s disease.52 No biological data have yet been reported. However, representative examples and a full QC distribution taken from a 10% random selection of the final library are shown in Figs. 10 and 11. 

Unknown elements of primary sequence and zinc consensus determine the tertiary fold, indicating that the parallel structural and sequence categories classifing the zinc proteases is a result of the fortuitious selection of the proteases used for structural analysis. 

Recently, closely related isothiazolidin-3-one S,S dioxide 167 was prepared and tested in vitro [54]. The R residue binds to primary specificity pockets of HLE and by modulating the R1 substitutent it is possible to obtain highly potent HLE inhibitors or compounds that are highly selective for other types of serine proteases (R = isobutyl for HLE inhibitors, R = Ph for cathepsin... 

Viral replication in the presence of indinavir selects for drug-resistant virus. The primary indinavir resistance mutations occur at HIV protease codons 46 (a methioiune-to-isoleucine or leucine), 82, and 84. However, secondary resistance mutations can accumulate at codons 10, 20, 24, 46, 54, 63, 71, 82, 84, and 90, and these are associated with clinical indinavir resistance as well as cross-resistance to other HIV protease inhibitors. 

In patients treated with ritonavir as the sole protease inhibitor, virus replication in the presence of drug selects for drug-resistance mutations. The primary ritonavir resistance mutation is usually at protease codon 82 (several possible substitutions for valine) or codon 84 (isoleucine-to-valine substitution). Additional mutations associated with increasing resistance occur at codons 20, 32, 46, 54, 63, 71, 84, and 90. High-level resistance requires accumulation of multiple mutations. 

Numerous experimental results have demonstrated that caspase-8 is the main caspase in the TNF family death receptor pathway (Fig. 1) whereas caspase-9 is the principal caspase of the mitochondrial pathway (Fig. 2) [17,18]. However, not all caspases are directly involved in apoptosis. The primary role of some caspases, including caspase-1, is the activation of pro-inflammatory cytokines. The inhibition of these proteases could thus be useful in controlling numerous diseases. The peptide drug VX-740, for instance, is a selective and reversible caspase-1 inhibitor that is intended to treat arthritis and other inflammatory diseases... 

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