title: Expedited solid-phase synthesis of fluorescently labeled and biotinylated aminoalkane diphenyl phosphonate affinity probes for chymotrypsin- and elastase-like serine proteases.
abstract: In this study, we report on a novel, expedited solid-phase approach for the synthesis of biotinylated and fluorescently tagged irreversible affinity based probes for the chymotrypsin and elastase-like serine proteases. The novel solid-phase biotinylation or fluorescent labeling of the aminoalkane diphenyl phosphonate warhead using commercially available Biotin-PEG-NovaTag or EDANS NovaTag resin permits rapid, facile synthesis of these reagents. We demonstrate the kinetic evaluation and utilization of a number of these irreversible inactivators for chymotrypsin-like (chymotrypsin/human cathepsin G) and elastase-like serine proteases. Encouragingly, these compounds display comparable potency against their target proteases as their N-benzyloxycarbonyl (Cbz)-protected parent compounds, from which they were derived, and function as efficient active site-directed inactivators of their target proteases. We subsequently applied the biotinylated reagents for the sensitive detection of protease species via Western blot, showing that the inactivation of the protease was specifically mediated through the active site serine. Furthermore, we also demonstrate the successful detection of serine protease species with the fluorescently labeled derivatives "in-gel", thus avoiding the need for downstream Western blotting. Finally, we also show the utility of biotinylated and pegylated affinity probes for the isolation/enrichment of serine protease species, via capture with immobilized streptavidin, and their subsequent identification via de novo sequencing. Given their selectivity of action against the serine proteases, we believe that these reagents can be exploited for the direct, rapid, and selective identification of these enzymes from biological milieu containing multiple protease subclasses.
authors.affiliation: School of Pharmacy, Queens University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast BT97BL, United Kingdom.
authors.forename: Brendan F
authors.initials: BF
authors.lastname: Gilmore
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Quinn
authors.forename: Thomas
authors.initials: T
authors.lastname: Duff
authors.forename: George R
authors.initials: GR
authors.lastname: Cathcart
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Scott
authors.forename: Brian
authors.initials: B
authors.lastname: Walker
mesh_terms: D000345:Affinity Labels / Q000138:chemical synthesis*; D019921:Biotinylation; D001713:Biphenyl Compounds / Q000138:chemical synthesis*; D020134:Catalytic Domain; D002918:Chymotrypsin / Q000032:analysis; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D063065:Organophosphonates; D010196:Pancreatic Elastase / Q000032:analysis; D057057:Serine Proteases / Q000032:analysis*
chemical_list: D000345:Affinity Labels; D001713:Biphenyl Compounds; D005456:Fluorescent Dyes; D063065:Organophosphonates; D057057:Serine Proteases; D002918:Chymotrypsin; D010196:Pancreatic Elastase