Proteolytic activity inhibition

Regulation of MMP activity is quite complex. These regulatory processes include transcriptional regulation, proteolytic activation, inhibition by the circulating protein a2-macroglobulin, and regulation by a class of inhibitors known as... 

A novel concept of using bioadhesive polymers as enzyme inhibitors has been developed [97]. Included are derivatives of poly acrylic acid, polycarbophil, and car-bomer to protect therapeutically important proteins and peptides from proteolytic activity of enzymes, endopeptidases (trypsin and a-chymotrypsin), exopeptidases (carboxypeptidases A and B), and microsomal and cytosolic leucine aminopeptidase. However, cysteine protease (pyroglutamyl aminopeptidase) is not inhibited by polycarbophil and carbomer [97]. 

Ruseler-van Embden, J. G. H., van Lieshout, L. M. C., Smits, S. A., van Kessel, ., Laman, J. D. (2004). Potato tuber proteins efficiently inhibit human faeeal proteolytic activity implications for treatment of perianal dermatitis. Fur. J. Clin. Invest., 34, 303-311. 

Ghorobekova (1987) showed the inhibitory effect of humic matter on protease activity. Inhibition kinetics are of mixed order, and humic acids can be used as a regulator of activity and biosynthesis of proteolytic enzymes. 

The MMPs are a family of zinc-dependent neutral endopep-tidases that share structural domains but differ in substrate specificity, cellular sources, and inductivity (Table I). All the MMPs are important for remodeling of the extra cellular matrix and share the following functional features (/) they degrade extracellular matrix components, including fibronectin, collagen, elastin, proteoglycans, and laminin, (//) they are secreted in a latent proform and require activation for proteolytic activity, (///) they contain zinc at their active site and need calcium for stability, (/V) they function at neutral pH, and (v) they are inhibited by specific tissue inhibitors of metalloproteinases (TIMPs). 

Denda et al. previously demonstrated40 that tran.s-4-aminomethyl cyclohexane carboxylic acid (/-AMCIIA), an anti-fibrinolytic agent that activates plasminogen, improved the barrier homeostasis and whole skin condition. After barrier disruption, proteolytic activity in the epidermis increased within 1 to 2 h. This increase was inhibited by t-AMCHA. Topical application of r-AMCHA or... 

This extremely facile restoration process indicates that the environment of the scissile bond in the complex is quite hydrophobic in nature so the dehydration reaction, which is highly endergonic in aqueous environment, proceeds unusually rapidly. One can therefore conclude that the Michaelis intermediate with the intact scissile bond is indeed the thermodynamically stable form and not the kinetically controlled one. The subtilisin is being entrapped in the complex since it is excessively stable, hence its proteolytic activity is inhibited by SSI. 

The pharmacodynamic profile of NPI-0052 is different from other proteasome inhibitors (bortezomib and carfilzomib) in that upon a single IV administration to mice, a sustained inhibition ( > 72 hours) of the main three 20.S proteolytic activities is observed in packed whole blood lysates (Figure 12.2A). Bortezomib has been reported to either have no effect on or to enhance the T-L activity, while carfilzomib specifically inhibits the CT-L 20V proteasome activity.14,31 Repeated NPI-0052 administration to rodents and monkeys leads to sustained dose-dependent inhibition of whole blood 20V proteasome activity, with higher inhibition observed after subsequent administrations and with partial recovery between consecutive NPI-0052 treatments. 

The first is the presence of proteolytic activities, which must be inhibited early in the procedure to prevent the degradation of other enzyme proteins. Second, the amount of protein present in these fluids is usually in excess of what an HPLC analytical column can handle without becoming clogged. And finally, these fluids often contain many low molecular weight compounds, either those added as nutrients or those present as a result of cellular metabolism. Since such compounds may resemble either the substrate or product, or both, of the enzymatic reaction under study, their presence in the reaction mixture could interfere with the assay. At the very least, such compounds will pass through the analytical column and appear on a chromatogram, confusing the experimental results. 

Traditionally, the specificity of proteases is determined using standard or optimized peptide libraries containing small recognition sites or, for de novo screening, phage display libraries (Richardson, 2002). These techniques may prove to be useful as a first screening approach. However, they are insufficient to predict the outcome of inhibiting a proteolytic activity in an in vivo situation. 

Stehlik C, de Martin R, Kumabashiri I, Schmid JA, Binder BR, Lipp J (1998) Nuclear factor (NF)-kappaB-regulated X-chromosome-linked iap gene expression protects endothelial cells from tumor necrosis factor alpha-induced apoptosis. J Exp Med 188 211-216 Stennicke HR, Deveraux QL, Humke EW, Reed JC, Dixit VM, Salvesen GS (1999) Caspase-9 ctin be activated without proteolytic processing. J Biol Chem 274 8359-8362 Sun XM, Butterworth M, MacFarlane M, Dubiel W, Ciechanover A, Cohen GM (2004) Caspase activation inhibits proteasome function during apoptosis. Mol Cell 14 81-93 Suzuki Y, Imai Y, Nakayama H, Takahashi K, Takio K, Takahashi R (2001) A serine protease, HtrA2, is released from the mitochondria and interacts with XIAP, inducing cell death. Mol Cell 8 613-621... 

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