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J Dairy Sci. 2014 Oct;97(10):5975-82. doi: 10.3168/jds.2014-8047. Epub 2014 Jul 23.

Effects of metal ions on growth, β-oxidation system, and thioesterase activity of Lactococcus lactis.

Author information

1
School of Food Science and Engineering, Harbin Institute of Technology, 202 Haihe Road, Harbin, Heilongjiang 150090, China; College of Food Science, Northeast Agricultural University, 59 Gongbin Road, Harbin, Heilongjiang 150030, China.
2
School of Food Science and Engineering, Harbin Institute of Technology, 202 Haihe Road, Harbin, Heilongjiang 150090, China. Electronic address: maying@hit.edu.cn.

Abstract

The effects of divalent metal ions (Ca(2+), Mg(2+), Fe(2+), and Cu(2+)) on the growth, β-oxidation system, and thioesterase activity of Lactococcus lactis were investigated. Different metal ions significantly influenced the growth of L. lactis: Ca(2+) and Fe(2+) accelerated growth, whereas Cu(2+) inhibited growth. Furthermore, Mg(2+) inhibited growth of L. lactis at a low concentration but stimulated growth of L. lactis at a high concentration. The divalent metal ions had significant effects on activity of the 4 key enzymes of the β-oxidation system (acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and thiolase) and thioesterase of L. lactis. The activity of acyl-CoA dehydrogenases increased markedly in the presence of Ca(2+) and Mg(2+), whereas it decreased with 1 mmol/L Fe(2+) or 12 mmol/L Mg(2+). All the metal ions could induce activity of enoyl-CoA hydratase. In addition, 12 mmol/L Mg(2+) significantly stimulated activity of L-3-hydroxyacyl-CoA dehydrogenase, and all metal ions could induce activity of thiolase, although thiolase activity decreased significantly when 0.05 mmol/L Cu(2+) was added into M17 broth. Inhibition of thioesterase activity by all 4 metal ions could be reversed by 2 mmol/L Ca(2+). These results help us understand the effect of metal ions on the β-oxidation system and thioesterase activity of Lactococcus lactis.

KEYWORDS:

Lactococcus lactis; metal ion; thioesterase; β-oxidation system

PMID:
25064652
DOI:
10.3168/jds.2014-8047
[Indexed for MEDLINE]
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