Macris B J
Appl Microbiol. 1975 Oct;30(4):503-6. doi: 10.1128/am.30.4.503-506.1975.
A fast uptake of the preservative benzoic acid was observed in Saccharomyces cerevisiae, reaching saturation in about two min and then remaining constant at this level. The strong dependence of benzoic acid uptake on pH was due to the relative distribution of molecular and ionic forms in solution and not to the pH itself. The molecular form was the only one taken up by the cells. The specificity of the uptake mechanism was evidenced by the pattern of irreversible heat inactivation of the uptake system resembling protein denaturation by heat. Furthermore, the effect of temperature on the uptake was similar to that observed in enzymic reactions, whereas the kinetic data of uptake conformed to the Michaelis-Menten curve of saturation with a Km of 1.54 X 10(-2) M and Vmax of 3 X 10(-3) M/10s. The evidence presented in this paper indicates that compounds of protein nature are involved in the uptake of this preservative.
在酿酒酵母中观察到防腐剂苯甲酸的快速摄取，约两分钟达到饱和，然后在此水平保持恒定。苯甲酸摄取对pH的强烈依赖性是由于溶液中分子和离子形式的相对分布，而非pH本身。分子形式是细胞摄取的唯一形式。摄取系统不可逆热失活模式类似于蛋白质热变性，证明了摄取机制的特异性。此外，温度对摄取的影响与酶促反应中观察到的相似，而摄取的动力学数据符合米氏饱和曲线，Km为1.54×10⁻² M，Vmax为3×10⁻³ M/10s。本文提供的证据表明，蛋白质性质的化合物参与了这种防腐剂的摄取。
