Search results for "Protease"

Non-Saccharomyces Yeasts: An Enzymatic Unexplored World to be Exploited

2019

Abstract Fermentation, to obtain alcoholic beverages, is a process which implies the interaction of various microorganisms. This metabolic process is due to the action of yeasts, which can be divided into two groups, the Saccharomyces yeasts, particularly S. cerevisiae, and the non-Saccharomyces yeasts. Although they are considered spoilage microorganisms of the fruits, non-Saccharomyces yeasts possess some interesting applied characteristics and can be used in food industry. Some of the compounds produced by these microorganisms may be beneficial and improve the characteristics of the fermented beverages. In this chapter, recent advances in glycosidase, xylanase, lipase, esterase, protease…

Putative high mobility group non-histone chromosomal proteins from pea (Pisum sativum)

1991

Abstract Three putative HMG proteins, 1P, 2P and 3P have been isolated from pea ( Pisum sativum L. cv. Lincoln) nuclei by extraction with either 5% perchloric acid or 0.35 M NaCl and purified by preparative electrophoresis. The amino acid analysis showed many of the typical features of the HMG proteins, although 1P and 2P possess a somewhat reduced content of acidic amino acids and 3P has less than 20% basic amino acids. Peptide mapping with Staphylococcus aureus V8 protease suggested that none of the proteins are proteolytic products of histone H1.

Unraveling the SARS-CoV-2 Main Protease Mechanism Using Multiscale DFT/MM Methods

2020

<p>We present a detailed theoretical analysis of the reaction mechanism of proteolysis catalyzed by the main protease of SARS-CoV-2. Using multiscale simulation methods, we have characterized the interactions stablished by a peptidic substrate in the active site and then we have explored the free energy landscape associated to the acylation and de-acylation steps of the proteolysis reaction, characterizing the transition states of the process. Our mechanistic proposals can explain most of the experimental observations made on the highly similar ortholog protease of SARS-CoV. We point out to some key interactions that may facilitate the acylation process and thus can be crucial in the …

The N-glycan processing in HT-29 cells is a function of their state of enterocytic differentiation. Evidence for an atypical traffic associated with …

1991

International audience; When the human colon cancer cells HT-29 undergo enterocytic differentiation, they correctly process their N-glycans, whereas their undifferentiated counterpart are unable to process Man9-8-GlcNAc2 species, the natural substrate of alpha-mannosidase I. As this enzyme is fully active in both HT-29 cell populations, we hypothesize that N-glycoproteins are unable to reach the cis Golgi, the site where alpha-mannosidase I has been localized. We have demonstrated this point by using 1-deoxymannojirimycin, leupeptin, and monensin. In the presence of 1-deoxymannojirimycin, a specific inhibitor of alpha-mannosidase I, differentiated HT-29 cells, as expected, accumulate Man9-8…

Synthesis of C3/C1-Substituted Tetrahydroisoquinolines

2015

A broad biological screening of the natural alkaloid N-methylisosalsoline (2) extracted from Hammada scoparia leaves against a panel of human and parasitic proteases revealed an interesting activity profile of 2 towards human 20S proteasome. This outcome suggests that the 1,2,3,4-tetrahydroisoquinoline skeleton may be exploited as a template for the development of novel anticancer agents. In this article, we report the synthesis and chemical characterization of a new series of isosalsoline-type alkaloids (10-11) with variations at N2 and C3 positions with respect to the natural Compound 2, obtained by a synthetic strategy that involves the Bischler-Napieralski cyclization. The substrate for…

Secretion of haemolysins and proteases by Aeromonas hydrophila EO63: separation and characterization of the serine protease (caseinase) and the metal…

2004

C . E S T E V E A N D T . H . B I R K B E C K . 2004. Aims: To determine the haemolysins and proteases excreted by the virulent strain EO63 of Aeromonas hydrophila grown in complex media and to then fractionate and characterize them, in particular those with elastolytic activity. Methods and Results: The amount of haemolytic and proteolytic activity in EO63 culture supernatants was dependent on the culture media used. In all media, haemolysins appeared during the phase of active growth and haemolytic activity decreased quickly thereafter, as previously described for aerolysin. In contrast, proteases were mainly released during the stationary phase. Serine protease activity in EO63 culture s…

2012

Diazepinomicin is a dibenzodiazepine alkaloid with an unusual structure among the known microbial metabolites discovered so far. Diazepinomicin was isolated from the marine sponge-associated strain Micromonospora sp. RV115 and was identified by spectroscopic analysis and by comparison to literature data. In addition to its interesting preclinical broad-spectrum antitumor potential, we report here new antioxidant and anti-protease activities for this compound. Using the ferric reducing antioxidant power (FRAP) assay, a strong antioxidant potential of diazepinomicin was demonstrated. Moreover, diazepinomicin showed a significant antioxidant and protective capacity from genomic damage induced …

Inhibition of glycosaminoglycan modification of perlecan domain I by site-directed mutagenesis changes protease sensitivity and laminin-1 binding act…

1998

AbstractGlycosaminoglycan attachment to perlecan domain I (173 residues) was completely prevented by site-directed mutagenesis of Ser-65, Ser-71 and Ser-76 as shown by recombinant production in mammalian cells. This did not interfere with the proper folding of the domain's SEA module but enhanced its sensitivity to neutral proteases. Lack of substitution also abolished binding to the two major heparin binding sites of laminin-1.

Botulinum A and the light chain of tetanus toxins inhibit distinct stages of Mg.ATP-dependent catecholamine exocytosis from permeabilised chromaffin …

1994

Susceptibilities of Mg.ATP-independent and Mg.ATP-requiring components of catecholamine secretion from digitonin-permeabilised chromaffin cells to inhibition by Clostridial botulinum type A and tetanus toxins were investigated. These toxins are Zn(2+)-dependent proteases which specifically cleave the 25-kDa synaptosomal-associated protein (SNAP-25) and vesicle-associated membrane protein (VAMP) II, respectively. When applied to permeabilised chromaffin cells they rapidly inhibited secretion in the presence of Mg.ATP but the catecholamine released in the absence of Mg.ATP, thought to represent fusion of primed granules, was not perturbed. The toxins can exert their effects per se in the abse…

Processing of tetanus and botulinum A neurotoxins in isolated chromaffin cells.

1995

Tetanus and botulinum A neurotoxins were introduced into the cytosol of chromaffin cells by means of an electric field in which the plasma membrane is forced to form pores of approximately 1 micron at the sites facing the electrodes. As demonstrated by electron microscopy, both [125I] and gold-labelled tetanus toxin (TeTx) diffuse through these transient openings. Dichain-TeTx, with its light chain linked to the heavy chain by means of a disulfide bond, causes the block of exocytosis to develop more slowly than does the purified light chain. The disulfide bonds, which in both toxins hold the subunits together, were cleaved by the intrinsic thioredoxin-reductase system. Single chain TeTx, in…