Cited by 76Probiotics and Fermented FoodsEnzyme Production and CharacterizationBacterial Genetics and Biotechnology

Mechanism of Proteinase Release from Lactococcus lactis subsp. cremoris Wg2

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Laan, Harry, Konings, Wil N.·1989·Applied and Environmental Microbiology

Abstract

The procedure generally used for the isolation of extracellular, cell-associated proteinases of Lactococcus lactis species is based on the release of the proteinases by repeated incubation and washing of the cells in a Ca-free buffer. For L. lactis subsp. cremoris Wg2, as many as five incubations for 30 min at 29 degrees C are needed in order to liberate 95% of the proteinase. Proteinase release was not affected by chloramphenicol, which indicates that release is not the result of protein synthesis during the incubations. Ca inhibited, while ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) stimulated, proteinase release from the cells. The pH optimum for proteinase release ranged between 6.5 and 7.5, which was higher than the optimum pH of the proteinase measured for casein hydrolysis (i.e., 6.4). Treatment of cells with the serine proteinase inhibitor phenylmethylsulfonyl fluoride prior to the incubations in Ca-free buffer reduced the release of the proteinase by 70 to 80%. The residual proteinase remained cell associated but could be removed by the addition of active L. lactis subsp. cremoris Wg2 proteinase. This suggests that proteinase release from cells of L. lactis subsp. cremoris Wg2 is the result of autoproteolytic activity. From a comparison of the N-terminal amino acid sequence of the released proteinase with the complete amino acid sequence determined from the nucleotide sequence of the proteinase gene, a protein of 180 kilodaltons would be expected. However, a proteinase with a molecular weight of 165,000 was found, which indicated that further hydrolysis had occurred at the C terminus.

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Crossref · 10.1128/aem.55.12.3101-3106.1989

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Authors
Laan, H., & Konings, W. N.
Affiliations
University of Groningen (NL)
Venue
Applied and Environmental Microbiology
Published
1989-12
Volume
55
Issue
12
Pages
3101-3106
ISSN
  • 0099-2240 (ISSN-L)
  • 1098-5336
OpenAlex
W1590961427
Cited by
76
References
28
Citations by year
2025: 1 · 2022: 1 · 2021: 1 · 2020: 1 · 2019: 2 · 2018: 1 · 2017: 1 · 2015: 1 · 2014: 1 · 2013: 1 · 2012: 4
FWCI
11.63
Type
journal article
Language
en
Open access
Locations
  • Applied and Environmental Microbiology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • University of Groningen research database (University of Groningen / Centre for Information Technology) (submittedVersion)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Food Science › Probiotics and Fermented Foods
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Biotechnology › Enzyme Production and Characterization
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Bacterial Genetics and Biotechnology
Keywords
Lactococcus lactis subsp. cremoris, extracellular protease, calcium dependence, EGTA, phenylmethylsulfonyl fluoride, serine protease, casein hydrolysis, N-terminal sequence, cell-associated enzymes

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