Peptide boronic acids. Versatile synthetic ligands for affinity chromatography of serine proteinases

Boron chemicals in diagnosis and therapeutics

Advances in the field of boron chemistry have expanded the application of boron from material use to medicine. Boron-based drugs represent a new class of molecules that possess several biomedical applications including use as imaging agents for both optical and nuclear imaging as well as therapeutic agents with anticancer, antiviral, antibacterial, antifungal and other disease-specific activities. For example, bortezomib (Velcade(®)), the only drug in clinical use with boron as an active element, was approved in 2003 as a proteasome inhibitor for the treatment of multiple myeloma and non-Hodgkin's lymphoma. Several other boron-based compounds are in various phases of clinical trials, which illustrates the promise of this approach for medicinal chemists working in the area of boron chemistry. It is expected that in the near future, several boron-containing drugs should become available in the market with better efficacy and potency than existing drugs. This article discusses the current status of the development of boron-based compounds as diagnostic and therapeutic agents in humans.

Inhibitors of cathepsin G: a patent review (2005 to present)

INTRODUCTION

Cathepsin G (CatG) is a neutral proteinase originating from human neutrophils. It displays a unique dual specificity (trypsin- and chymotrypsin-like); thus, its enzymatic activity is difficult to control. CatG is involved in the pathophysiology of several serious human diseases, such as chronic obstructive pulmonary disease (COPD), Crohn's disease, rheumatoid arthritis, cystic fibrosis and other conditions clinically manifested by excessive inflammatory reactions. For mentioned reasons, CatG was considered as good molecular target for the development of novel drugs. However, none of them have yet entered the market as novel therapeutic agents.

AREAS COVERED

This article presents an in-depth and detailed analysis of the therapeutic potential of CatG inhibitors based on a review of patent applications and academic publishing disclosed in patents and patent applications (1991 - 2012), with several exceptions for inhibitors retrieved from academic articles.

EXPERT OPINION

Among the discussed inhibitors of CatG, examples corresponding to derivatives of β-ketophosphonic acids, aminoalkylphosphonic esters and boswellic acids (BAs) could be regarded as the most promising. The most promising one seems to be analogues of compounds of Nature's origin (peptidic and BA derivates). Nevertheless, nothing is currently known about the clinical disposition of any of the CatG inhibitors discovered so far. This latter point suggests that there is still a lot of work to do in the design of stable, pharmacologically active compounds able to specifically regulate the in vivo activity of cathepsin G.

Affinity Chromatography of Tryptases: Design, Synthesis and Characterization of a Novel Matrix-Bound Bivalent Inhibitor

beta-Tryptases are mast cell-derived serine proteases that are enzymatically active in the form of an oligomer consisting of four subunits each with trypsin-like activity. The active-site clefts, which are directed toward the central pore of the tetramer, form spatial arrays of four negatively charged S1 binding pockets. Therefore, dibasic inhibitors of appropriate geometry can bind in a bivalent fashion to neighboring subunits. We have recently identified a potent bivalent inhibitor (K(i)=18 nM), based on the bifunctional scaffold cyclo-(-D-Asp-L-Asp-) and the arginine mimetic dl-3-aminomethyl-phenylalanine methyl ester as a ligand for S1 pockets that takes advantage of the this unique tetrameric geometry. To generate an affinity matrix, the bivalent ligand was modified and immobilized on a Sepharose matrix by use of the PEG derivative Jeffamine ED 900 as spacer. This matrix selectively recognizes and binds beta-tryptase from crude protein mixtures and thus is useful as a geometry-driven means of isolating and purifying human mast cell tryptases.