title: Proteome analysis of Lactobacillus helveticus H9 during growth in skim milk.
abstract: Lactobacillus helveticus H9 was isolated from traditionally fermented yak milk in Tibet (China) with the ability to produce the antihypertensive peptides Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) during milk fermentation. To understand the changes in the protein expression of L. helveticus H9, proteome analysis was performed at 3 different growth stages, lag phase (pH 6.1), log phase (pH 5.1), and stationary phase (pH 4.5) using 2-dimensional electrophoresis (2-DE). Further analysis showed that 257 differential protein spots were found and 214 protein spots were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The cellular functions of the differentially expressed proteins were complex. Interestingly, the proteolytic system-related proteins aminopeptidase N (PepN), aminopeptidase E (PepE), endopeptidase O2 (PepO2), and oligopeptide transport system permease protein (OppC) were observed only on the maps of pH 5.1 and pH 4.5, which was consistent with the presence of angiotensin I-converting enzyme (ACE)-inhibitory peptides VPP and IPP during these 2 growth stages (log phase and stationary phase). These results, combined with a previous study of gene expression of the proteolytic system, led us to conclude that the Opp transport system, pepE, and pepO2 are likely related to the production of ACE-inhibitory peptides.
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, P. R. China, 214122.
authors.forename: Y F
authors.initials: YF
authors.lastname: Chen
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018; The Institute of Products Quality Inspection and Research Inner Mongolia Autonomous Region, Huhhot, P. R. China, 010070.
authors.forename: W J
authors.initials: WJ
authors.lastname: Zhao
authors.affiliation: Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, P. R. China, 214122; College of Food Science, Shenyang Agricultural University, Shenyang, P. R. China, 110866.
authors.forename: R N
authors.initials: RN
authors.lastname: Wu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, P. R. China, 214122.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Sun
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018.
authors.forename: W Y
authors.initials: WY
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018.
authors.forename: J C
authors.initials: JC
authors.lastname: Wang
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018.
authors.forename: M
authors.initials: M
authors.lastname: Bilige
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Huhhot, P. R. China, 010018; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, P. R. China, 214122. Electronic address: hepingdd@vip.sina.com.
authors.forename: H P
authors.initials: HP
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D002417:Cattle; D015180:Electrophoresis, Gel, Two-Dimensional; D010450:Endopeptidases / Q000378:metabolism; D005260:Female; D005285:Fermentation; D006973:Hypertension / Q000628:therapy; D052198:Lactobacillus helveticus / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D008892:Milk / Q000382:microbiology*; D009842:Oligopeptides / Q000032:analysis / Q000378:metabolism; D010455:Peptides / Q000032:analysis; D007703:Peptidyl-Dipeptidase A / Q000032:analysis / Q000378:metabolism; D059748:Proteolysis; D020543:Proteome; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018609:Tibet
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D009842:Oligopeptides; D010455:Peptides; D020543:Proteome; C489032:isoleucyl-prolyl-proline; C489031:valyl-prolyl-proline; C037230:oligopeptide permease, Bacteria; D010450:Endopeptidases; D007703:Peptidyl-Dipeptidase A
keywords: Lactobacillus helveticus H9; proteolytic system; proteomics