Department of Food Science, New Jersey Agricultural Experiment Station, Cook College, Rutgers-the State University, New Brunswick, New Jersey 08903-0231, and Department of Biochemistry, Mount Sinai School of Medicine of the City University of New York, New York, New York 10029.
Appl Environ Microbiol. 1992 Mar;58(3):891-4. doi: 10.1128/aem.58.3.891-894.1992.
Pyruvate is the substrate for diacetyl and acetoin synthesis by lactobacilli. Exogenous pyruvate stimulates acetoin production when glucose is present as an energy source. In Lactobacillus plantarum ATCC 8014, the energy derived from glucose via glycolysis generated a constant proton motive force of about -120 mV. At a low external pH, energized cells rapidly transported and accumulated pyruvate but did not do so when they were deenergized by nigericin. When large amounts of pyruvate were transported and subsequently accumulated internally, the cotransported protons rapidly lowered the internal pH. The conversion of pyruvate to acetoin instead of acidic end products contributed to the maintenance of pH homeostasis. This is the first report showing that the conversion of pyruvate to acetoin serves as a mechanism of pH homeostasis.
丙酮酸是乳杆菌合成二乙酰和乙酰丁酮的底物。当葡萄糖作为能源存在时，外源性丙酮酸会刺激乙酰丁酮的产生。在植物乳杆菌 ATCC 8014 中，通过糖酵解从葡萄糖中获得的能量产生约-120 mV 的恒定质子动力。在较低的外部 pH 值下，高能细胞迅速运输和积累丙酮酸，但当它们被 Nigericin 去能时则不会这样做。当大量丙酮酸被运输并随后在内部积累时，共运输的质子会迅速降低内部 pH 值。丙酮酸转化为乙酰丁酮而不是酸性终产物有助于维持 pH 平衡。这是第一个表明将丙酮酸转化为乙酰丁酮可作为 pH 平衡机制的报告。
