title: Characterization of a New Cell Envelope Proteinase PrtP from Lactobacillus rhamnosus CGMCC11055.
abstract: Cell envelope proteinases (CEPs) play essential roles in lactic acid bacteria growth in milk and health-promoting properties of fermented dairy products. The genome of Lactobacillus rhamnosus CGMCC11055 possesses two putative CEP genes prtP and prtR2, and the PrtP displays the distinctive domain organization from PrtR2 reported. The PrtP was purified and biochemically characterized. The results showed that the optimal activity occurred at 44 °C, pH 6.5. p-Amidinophenylmethylsulfonyl fluoride obviously inhibited enzymatic activity, suggesting PrtP was a member of serine proteinases. Under the optimal conditions, β-casein was a favorite substrate over αS1- and κ-casein, and 35 oligopeptides were identified in the β-casein hydrolysate, including the phosphoserine peptide and bioactive isoleucine-proline-proline. By analysis of the amino acid sequences of those oligopeptides, proline was the preferred residue at the breakdown site. Therefore, we speculated that PrtP was a new type of CEPs from Lb. rhamnosus.
authors: State Key Laboratory of Microbial Technology, Shandong University , Jinan 250100, P. R. China.
authors: Tingting
authors: T
authors: Guo
authors: State Key Laboratory of Microbial Technology, Shandong University , Jinan 250100, P. R. China.
authors: Xudong
authors: X
authors: Ouyang
authors: State Key Laboratory of Microbial Technology, Shandong University , Jinan 250100, P. R. China.
authors: Yongping
authors: Y
authors: Xin
authors: State Key Laboratory of Microbial Technology, Shandong University , Jinan 250100, P. R. China.
authors: Yue
authors: Y
authors: Wang
authors: State Key Laboratory of Microbial Technology, Shandong University , Jinan 250100, P. R. China.
authors: Susu
authors: S
authors: Zhang
authors: State Key Laboratory of Microbial Technology, Shandong University , Jinan 250100, P. R. China.
authors: Jian
authors: J
authors: Kong
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D052201:Lacticaseibacillus rhamnosus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000072417:Protein Domains; D057057:Serine Proteases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D010447:Peptide Hydrolases; D057057:Serine Proteases
keywords: Lactobacillus rhamnosus; breakdown pattern; cell envelope proteinase; domain structure; β-casein hydrolysis