Proteolytic enzymes

About: Proteolytic enzymes is a research topic. Over the lifetime, 23096 publications have been published within this topic receiving 835544 citations.

Plasmid-associated bacteriocin production by a strain of Carnobacterium piscicola from meat.

Abstract: Carnobacterium piscicola LV17 isolated from vacuum-packed meat produces bacteriocin(s) that is active against closely related lactic acid bacteria, Enterococcus spp., and a strain of Listeria monocytogenes but not against gram-negative bacteria. The bacteriocin has a bactericidal mode of action, is heat resistant, and is stable over a wide range of pH but is inactivated by proteolytic enzymes. Sensitive and resistant cells were shown to adsorb the bacteriocin, but cell death depended on contact of the bacteriocin with the cell membrane. Bacteriocin production is detected early in the growth cycle of the organism in APT broth, but it is not produced in APT broth adjusted to pH 5.5. Bacteriocin production and resistance to the bacteriocin produced are associated with two plasmids of 40 and 49 megadaltons. The possibility that two bacteriocins are produced is indicated because the inhibitory substances of the mutant strains containing either the 40- or 49-megadalton plasmids have different antimicrobial spectra.

Trichloroacetic acid-induced protein precipitation involves the reversible association of a stable partially structured intermediate

Abstract: Sample preparation for proteomic analysis involves precipitation of protein using 2,2,2-trichloroacetic acid (TCA). In this study, we examine the mechanism of the TCA-induced protein precipitation reaction. TCA-induced protein precipitation curves are U-shaped and the shape of the curve is observed to be independent of the physicochemical properties of proteins. TCA is significantly less effective in precipitating unfolded states of proteins. Results of the 1-anilino-8-napthalene sulfonate (ANS) and size-exclusion chromatography, obtained using acidic fibroblast growth factor (aFGF), show that a stable "molten globule-like" partially structured intermediate accumulates maximally in 5% (w/v) of trichloroacetate. Urea-induced unfolding and limited proteolytic digestion data reveal that the partially structured intermediate is significantly less stable than the native conformation. (1)H-(15)N chemical shift perturbation data obtained using NMR spectroscopy indicate that interactions stabilizing the beta-strands at the N- and C- terminal ends (of aFGF) are disrupted in the trichloroacetate-induced "MG-like" state. The results of the study clearly demonstrate that TCA-induced protein precipitation occurs due to the reversible association of the "MG-like" partially structured intermediate state(s). In our opinion, the findings of this study provide useful clues toward development of efficient protocols for the isolation and analysis of the entire proteome.