Division of Food Microbiology and Bioprocesses, Department of Food, Environmental and Nutritional Sciences-DeFENS, Università degli Studi di Milano, 2 Celoria, 20134 Milan, Italy.
J Ind Microbiol Biotechnol. 2013 May;40(5):489-94. doi: 10.1007/s10295-013-1239-9. Epub 2013 Mar 5.
Through the analysis of the recently available genome shotgun sequence of Enterococcus italicus DSM 15952(T) type strain (Accession PRJNA61487, ID 61487), we found the presence of a gene encoding a bifunctional enzyme, termed γ-GCS-GS or GshF, involved in glutathione production and not influenced by feedback inhibition. The gshF gene exhibited high nucleotide and amino acid sequence similarity to other reported sequences from the Enterococcus genus and was constitutively expressed both in osmotic shock or in common cultural conditions. Several experimental studies concerning the culture medium, physiological stress, cell extract obtainment, and scaling-up showed that in selected conditions E. italicus was able to accumulate up to 250 μM of intracellular glutathione, which represented the main thiol group present into the cells. This is the first report regarding the production of glutathione by E. italicus, a species that could be used as a safe adjunct culture for glutathione-enriched dairy foods.
通过对肠球菌意大利亚种 DSM 15952(T) 模式菌株的全基因组鸟枪法序列（登录号 PRJNA61487，ID 61487）进行分析，我们发现了一个编码双功能酶的基因，称为 γ-GCS-GS 或 GshF，该酶参与谷胱甘肽的生产，不受反馈抑制的影响。gshF 基因与其他肠球菌属报道的序列具有高度核苷酸和氨基酸序列相似性，在渗透休克或普通培养条件下均呈组成型表达。几项关于培养基、生理应激、细胞提取物获取和放大的实验研究表明，在选定的条件下，肠球菌意大利亚种能够积累高达 250μM 的细胞内谷胱甘肽，这是细胞中存在的主要巯基。这是关于肠球菌意大利亚种生产谷胱甘肽的首次报道，该种可以作为富含谷胱甘肽的乳制品的安全辅助培养物。
