Eriksen S H, Jensen B, Schneider I, Kaasgaard S, Olsen J
1. Department of General Microbiology, University of Copenhagen, Denmark.
Appl Microbiol Biotechnol. 1995 Mar;42(6):945-50. doi: 10.1007/BF00191195.
The uptake of phenoxyacetic acid by two different strains of Penicillium chrysogenum was studied. Phenoxyacetic acid (POA) was taken up by P. chrysogenum in a defined medium. Plots of initial velocity of POA uptake versus external substrate concentration, in the range 2-5000 microM, gave linear plots. Uptake of POA by induced and uninduced cells was identical. The initial velocity of POA uptake decreased as the pH of the suspension was increased from 5.4 to 7.2; the decrease closely paralleled the decline in the non-ionic form of the acid over this pH range. The initial velocity of POA uptake was not affected by the presence of phenylacetic acid. POA uptake proceeded until the cellular concentration was equal to the external concentration. It is concluded that POA is passively transported into P. chrysogenum by unmediated diffusion.
研究了两种不同产黄青霉菌株对苯氧乙酸的摄取情况。在特定培养基中，产黄青霉摄取了苯氧乙酸（POA）。在2 - 5000微摩尔范围内，POA摄取的初始速度与外部底物浓度的关系图呈线性。诱导细胞和未诱导细胞对POA的摄取情况相同。随着悬浮液pH值从5.4增加到7.2，POA摄取的初始速度降低；在这个pH范围内，这种降低与酸的非离子形式的下降密切平行。苯乙酸的存在不影响POA摄取的初始速度。POA摄取一直持续到细胞内浓度等于外部浓度。得出的结论是，POA通过非介导扩散被动转运到产黄青霉中。
