Pearce Amanda K, Booth Ian R, Brown Alistair J P
Molecular and Cell Biology, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK1.
Microbiology (Reading). 2001 Feb;147(Pt 2):403-410. doi: 10.1099/00221287-147-2-403.
The mechanisms by which the weak acid preservative benzoic acid inhibits the growth of Saccharomyces cerevisiae have been investigated. A reduction in the pyruvate kinase level, which decreases glycolytic flux, did not increase the sensitivity of yeast to benzoic acid. However, a decrease in 6-phosphofructo-1-kinase (PF1K), which does not affect glycolytic flux, did increase sensitivity to benzoic acid. Also, resistance was increased by elevating PF1K levels. Hence, resistance to benzoic acid was not dependent upon optimum glycolytic flux, but upon an adequate PF1K activity. Benzoic acid was shown to depress fructose 2,6-bisphosphate levels in YKC14, a mutant with low PF1K levels. This effect was partially suppressed by overexpressing constitutively active 6-phosphofructo-2-kinase (Pfk26(Asp644)) or by inactivating fructose-2,6-bisphosphatase (in a Deltafbp26 mutant). The inactivation of PF2K (in a Deltapfk26 Deltapfk27 mutant) increased benzoic acid sensitivity. Therefore, the antimicrobial effects of benzoic acid can be relieved, at least in part, by the genetic manipulation of PF1K or fructose 2,6-bisphosphate levels.
对弱酸防腐剂苯甲酸抑制酿酒酵母生长的机制进行了研究。丙酮酸激酶水平降低会减少糖酵解通量，但这并未增加酵母对苯甲酸的敏感性。然而，6-磷酸果糖-1-激酶（PF1K）水平降低虽不影响糖酵解通量，却确实增加了对苯甲酸的敏感性。此外，提高PF1K水平可增强抗性。因此，对苯甲酸的抗性并非取决于最佳糖酵解通量，而是取决于足够的PF1K活性。研究表明，苯甲酸会降低PF1K水平较低的突变体YKC14中果糖-2,6-二磷酸的水平。组成型活性6-磷酸果糖-2-激酶（Pfk26(Asp644)）过表达或果糖-2,6-二磷酸酶失活（在Deltafbp26突变体中）可部分抑制这种作用。PF2K失活（在Deltapfk26 Deltapfk27突变体中）会增加对苯甲酸的敏感性。因此，至少部分地通过对PF1K或果糖-2,6-二磷酸水平进行基因操作，可以减轻苯甲酸的抗菌作用。
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