1. Repressive processing of antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, in Lactobacillus helveticus fermented milk by added peptides.
- Author
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Wakai T, Yamaguchi N, Hatanaka M, Nakamura Y, and Yamamoto N
- Subjects
- Amino Acids pharmacology, Animals, Antihypertensive Agents chemistry, Caseins chemistry, Caseins metabolism, Endopeptidases genetics, Endopeptidases metabolism, Gene Expression Regulation, Bacterial, Lactobacillus helveticus cytology, Lactobacillus helveticus enzymology, Lactobacillus helveticus genetics, Milk chemistry, Oligonucleotide Array Sequence Analysis, Proteolysis drug effects, Transcriptome, Antihypertensive Agents metabolism, Fermentation, Lactobacillus helveticus metabolism, Milk metabolism, Oligopeptides metabolism, Peptides pharmacology
- Abstract
Lactobacillus helveticus can release the antihypertensive peptides, Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP), from casein in fermented milk by a specific proteolytic system. To better understand the regulation of gene expression of the proteolytic enzymes thought to link to the processing of both antihypertensive peptides in L. helveticus, microarray analysis for whole gene expression in the presence and absence of added peptides in the fermented milk was studied. The productivity of both VPP and IPP in L. helveticus CM4 fermented milk was repressed by adding 2% quantity of Peptone as peptide mixture to the milk. Among the selected 13 amino acids, Gly, Ile, Leu, Phe, Met, Ser and Val were effective in the repression of the productivity of VPP and IPP in the fermented milk. The activity of the cell wall-associated proteinase, which may play a key role in the processing of the two antihypertensive peptides, was significantly repressed by the addition of the 2% quantity of Peptone into the fermented milk. By DNA microarray analysis it was found that prtH2 corresponding to the cell wall-associated proteinase gene, most of the endopeptidase genes such as pepE, pepO1, pepO2 and pepO3, most of the oligopeptide transporter genes, such as dppA2, dppB, dppC, dppD and dppF, most likely involved in the processing of VPP and IPP were down-regulated. These results suggest that amino acids released from milk peptides in the fermented milk might down-regulate the gene expressions of some of the proteolytic enzymes and may cause repression of the release of VPP and IPP in L. helveticus fermented milk., (Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)
- Published
- 2012
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