A novel metalloprotease from Bacillus cereus for protein fibre processing

Abstract

A novel protease produced by Bacillus cereus grown on wool as carbon and nitrogen source was purified. B. cereus protease is a neutral metalloprotease with a molecular mass of 45.6 kDa. The optimum activity was at 45 • C and pH 7.0. The substrate specificity was assessed using oxidized insulin B-chain and synthetic peptide substrates. The cleavage of the insulin B-chain was determined to be Asn 3 , Leu 6 , His 10-Leu 11 , Ala 14 , Glu 21 , after 12 h incubation. Among the peptide substrates, the enzyme did not exhibit activity towards ester substrates; with p-nitroanilide, the kinetic data indicate that aliphatic and aromatic amino acids were the preferred residues at the P 1 position. For furylacryloyl peptides substrates, which are typical substrates for thermolysin, the enzyme exhibited high hydrolytic activity with a K m values of 0.858 and 2.363 mM for N-(3-[2-Furyl]acryloyl)-Ala-Phe amide and N-(3-[2-Furyl]acryloyl)-Gly-Leu amide, respectively. The purified protease hydrolysed proteins substrates such as azocasein, azocoll, keratin azure and wool.

Iron and Quorum Sensing Coordinately Regulate the Expression of Vulnibactin Biosynthesis in Vibrio vulnificus

“…The resulting plasmids, pGEM-TvvsAmt and pGEM-TvvsA, were both digested with restriction enzymes KpnI and XbaI and ligated into pHK0011 to construct pHVVSA168 and pHVVSA168mt, respectively. pHVVSA168 and pHVVSA168mt were introduced into wild-type V. vulnificus MO6-24/O, ⌬luxO, and ⌬luxO⌬smcR strains by bi-parental mating using S17-1 as donor (26). Exconjugants were selected on thiosulfate-citrate-bile salts-sucrose agar (TCBS) plates (Difco) supplemented with 2 g/ml tetracycline.…”

Keratinolytic Protease Production by Bacillus Cereus Strain Ps03 under Submerged Fermentation: Optimization and Characterization

“…Keratinolytic enzymes with similar molecular weights were isolated and characterized by several researchers. The molecular weight of keratinolytic enzyme was less than 50 kDa for Bacillus cereus (Sousa et al, 2007) and was 39.5 kDa for B. circulans (Rao et al, 2009). After molecular weight determination, the effect of pH on the activity and stability of keratinolytic protease enzyme was studied.…”

A Bacillus Strain Able to Hydrolyze Alpha- and Beta-Keratin

“…strain kr2 [47]. In contrast, the action of B. cereus protease on wool keratin generated an amino acid profile rich in glutamate, serine, leucine, proline, arginine, aspartic acid, and threonine residues [48], while phenylalanine, tyrosine, and lysine were the main amino acids produced in wool lysate of a recombinant strain of Bacillus subtilis [45].…”