Chemical annotation of the infusion of Less and its inhibitory potential on the elastase enzyme.

Less. is a shrub belonging to the Asteraceae. The infusion of its leaves has been used, in folk medicine of several South American countries, as anti-inflammatory and hypoglycaemic agent.

and elastase inhibition assessment assays of rosmarinic acid natural product from Linn.

The use of various herbs and their compounds has been a strategy widely used in the fight against various human diseases. For example, rosmarinic acid, a bioactive phenolic compound commonly found in Rosemary plants ( Labiatae), has multiple therapeutic benefits in different diseases, such as cancer. Therefore, the study aimed to evaluate and the inhibition potential of the enzyme Elastase from the porcine pancreas by rosmarinic acid isolated from the plant species Linn.

Discovery of a new isomannide-based peptidomimetic synthetized by Ugi multicomponent reaction as human tissue kallikrein 1 inhibitor.

Human kallikrein 1 (KLK1) is the most extensively studied member of this family and plays a major role in inflammation processes. From Ugi multicomponent reactions, isomannide-based peptidomimetic 10 and 13 where synthesized and showed low micromolar values of IC for KLK1 The most active compound (10) presented competitive mechanism, with three structural modifications important to interact with active site residues which corroborates its KLK1 inhibition. Finally, the most active compound also showed good ADMET profile, which indicates compound 10 as a potential hit in the search for new KLK1 inhibitors with low side effects.

The natural flavone fukugetin as a mixed-type inhibitor for human tissue kallikreins.

The human tissue kallikreins (KLK1-KLK15) comprise a family of 15 serine peptidases detected in almost every tissue of the human body and that actively participate in many physiological and pathological events. Some kallikreins are involved in diseases for which no effective therapy is available, as for example, epithelial disorders, bacterial infections and in certain cancers metastatic processes. In recent years our group have made efforts to find inhibitors for all kallikreins, based on natural products and synthetic molecules, and all the inhibitors developed by our group presented a competitive mechanism of inhibition.

Analysis of catalytic properties of tripeptidyl peptidase I (TTP-I), a serine carboxyl lysosomal protease, and its detection in tissue extracts using selective FRET peptide substrate.

Tripeptidyl peptidase I (TPP-I), also named ceroid lipofuscinosis 2 protease (CLN2p), is a serine carboxyl lysosomal protease involved in neurodegenerative diseases, and has both tripeptidyl amino- and endo- peptidase activities under different pH conditions. We developed fluorescence resonance energy transfer (FRET) peptides using tryptophan (W) as the fluorophore to study TPP-I hydrolytic properties based on previous detailed substrate specificity study (Tian Y. et al.

Specificity studies on Kallikrein-related peptidase 7 (KLK7) and effects of osmolytes and glycosaminoglycans on its peptidase activity.

KLK7 substrate specificity was evaluated by families of fluorescence resonance energy transfer (FRET) peptides derived from Abz-KLFSSK-Q-EDDnp (Abz=ortho-aminobenzoic acid and Q-EDDnp=glutaminyl-N-[2,4-dinitrophenyl] ethylenediamine), by one bead-one peptide FRET peptide library in PEGA resin, and by the FRET peptide libraries Abz-GXX-Z-XX-Q-EDDnp (Z and X are fixed and random natural amino acids, respectively). KLK7 hydrolyzed preferentially F, Y or M, and its S1' and S2' subsites showed selectivity for hydrophilic amino acids, particularly R and K. This set of specificities was confirmed by the efficient kininogenase activity of KLK7 on Abz-MISLM(↓)KRPPGFSPF(↓)RSSRI-NH2 ((↓)indicates cleavage), hydrolysis of somatostatin and substance P and inhibition by kallistatin.

Isomannide-based peptidomimetics as inhibitors for human tissue kallikreins 5 and 7.

Human kallikrein 5 (KLK5) and 7 (KLK7) are potential targets for the treatment of skin inflammation and cancer. Previously, we identified isomannide derivatives as potent and competitive KLK7 inhibitors. The introduction of N-protected amino acids into the isomannide-based scaffold was studied.

Isomannide derivatives as new class of inhibitors for human kallikrein 7.

Human kallikrein 7 (KLK7) is a potential target for the treatment of skin inflammation and cancer. Despite its potential, few KLK7-specific small-molecule inhibitors have been reported in the literature. As an extension of our program to design serine protease inhibitors, here we describe the in vitro assays and the investigation of the binding mechanism by molecular dynamics simulation of a novel class of pseudo-peptide inhibitors derived from isomannide.

Inhibition of cysteine proteases by a natural biflavone: behavioral evaluation of fukugetin as papain and cruzain inhibitor.

Cruzain is the major cysteine protease of Trypanosoma cruzi, the infectious agent responsible for Chagas disease, and cruzain inhibitors display considerable antitrypanosomal activity. In the present work we elucidated crystallographic data of fukugetin, a biflavone isolated from Garcinia brasiliensis, and investigated the role of this molecule as cysteine protease inhibitor. The kinetic analyses demonstrated that fukugetin inhibited cruzain and papain by a slow reversible type inhibition with K(I) of 1.

Substrate specificity of kallikrein-related peptidase 13 activated by salts or glycosaminoglycans and a search for natural substrate candidates.

KLK13 is a kallikrein-related peptidase preferentially expressed in tonsils, esophagus, testis, salivary glands and cervix. We report the activation of KLK13 by kosmotropic salts and glycosaminoglycans and its substrate specificity by employing a series of five substrates derived from the fluorescence resonance energy transfer (FRET) peptide Abz-KLRSSKQ-EDDnp. KLK13 hydrolyzed all these peptides only at basic residues with highest efficiency for R; furthermore, the S(3) to S(2)' subsites accepted most of the natural amino acids with preference also for basic residues.

Poliovirus 3C proteinase inhibition by organotelluranes.

The 3C proteinase, essential for human poliovirus (PV) replication, has unique characteristics as its three-dimensional structure resembles chymotrypsin, but its catalytic nucleophile is a cysteine SH group rather than the OH group of serine. Here, we describe the use of tellurium compounds as inhibitors of PV3C proteinase. A rapid, stoichiometric and covalent inactivation of PV3C was observed with both a chloro-telluroxetane and a bis-vinylic organotellurane.

Effects of magnesium ions on recombinant human furin: selective activation of hydrolytic activity upon substrates derived from virus envelope glycoprotein.

Here we report a detailed analysis of magnesium (Mg²+) ion effects on furin hydrolysis of fluorescent resonance energy transfer decapeptide substrates derived from canonical R-X-K/R-R furin cleavage motifs within certain viral envelope glycoproteins and eukaryotic proproteins. Using virus-derived sequences a selective activation of furin by Mg²+) ions was observed as a result of cooperativity between furin subsites. Furin hydrolysis of the peptides Abz-SRRHKR↓FAGV-Q-EDDnp (from measles virus fusion protein F₀ and Abz-RERRRKKR↓GLFG-Q-EDDnp (from Asian avian influenza A, H5N1) was activated between 60- and 80-fold by MgCl₂.

Studies on the catalytic mechanism of a glutamic peptidase.

Scytalidoglutamic peptidase (SGP) is the prototype of fungal glutamic peptidases that are characteristically pepstatin insensitive. These enzymes have a unique catalytic dyad comprised of Gln(53) and Glu(136) that activate a bound water molecule for nucleophilic attack on the carbonyl carbon atom of the scissile peptide bond. The hydrolysis by SGP at peptide bonds with proline in the P(1)' position is a rare event among peptidases that we investigated using the series of fluorescence resonance energy transfer peptides, Abz-KLXPSKQ-EDDnp, compared with the series Abz-KLXSSKQ-EDDnp.

Hydrolytic properties and substrate specificity of the foot-and-mouth disease leader protease.

Foot-and-mouth disease virus, a global animal pathogen, possesses a single-stranded RNA genome that, on release into the infected cell, is immediately translated into a single polyprotein. This polyprotein product is cleaved during synthesis by proteinases contained within it into the mature viral proteins. The first cleavage is performed by the leader protease (Lb(pro)) between its own C-terminus and the N-terminus of VP4.

A study of human furin specificity using synthetic peptides derived from natural substrates, and effects of potassium ions.

We explored furin substrate requirements in addition to the motif R-X-K/R-R using synthetic fluorescent resonance energy transfer (FRET) decapeptides. These decapeptides were derived from furin cleavage sites in viral coat glycoproteins and human and bacterial protein precursors. The hydrolysis by furin of most substrate was activated by K(+) ion, whereas kosmotropic anions of the Hofmeister series were inhibitors.

Kinetic analysis of salting activation of a subtilisin-like halophilic protease.

The secreted extracellular subtilase SR5-3 from Halobacillus sp. bacterium, isolated from the high-salt environment of Thai fish sauce, was utilized as a model halophilic serine protease. The dependence of salt activation on the size and structure of substrates was evaluated assaying the enzyme with Suc-AAPF-MCA and with the Fluorescence Resonance Energy Transfer (FRET) peptide Abz-AAPFSSKQ-EDDnp.