中间假丝酵母PYCC 4715中的高容量木糖转运
High capacity xylose transport in Candida intermedia PYCC 4715.
作者信息
Gárdonyi Márk, Osterberg Måns, Rodrigues Carla, Spencer-Martins Isabel, Hahn-Hägerdal Bärbel
机构信息
Centro de Recursos Microbiológicos (CREM), Faculty of Sciences and Technology, New University of Lisbon, 2829-516, Caparica, Portugal.
出版信息
FEMS Yeast Res. 2003 Mar;3(1):45-52. doi: 10.1111/j.1567-1364.2003.tb00137.x.
Xylose-utilising yeasts were screened to identify strains with high xylose transport capacity. Among the fastest-growing strains in xylose medium, Candida intermedia PYCC 4715 showed the highest xylose transport capacity. Maximal specific growth rate was the same in glucose and xylose media (mu(max)=0.5 h-1, 30 degrees C). Xylose transport showed biphasic kinetics when cells were grown in either xylose- or glucose-limited culture. The high-affinity xylose/proton symport system (Km = 0.2 mM, Vmax = 7.5 mmol h-1 g-1) was more repressed by glucose than by xylose. The less specific low-affinity transport system (K = 50 mM, Vmax = 11 mmol h-1 g-1) appeared to operate through a facilitated-diffusion mechanism and was expressed constitutively. Inhibition experiments showed that glucose is a substrate of both xylose transport systems.
筛选利用木糖的酵母以鉴定具有高木糖转运能力的菌株。在木糖培养基中生长最快的菌株中，中间假丝酵母PYCC 4715表现出最高的木糖转运能力。在葡萄糖和木糖培养基中的最大比生长速率相同（μ(max)=0.5 h-1，30℃）。当细胞在木糖或葡萄糖限制培养中生长时，木糖转运呈现双相动力学。高亲和力木糖/质子同向转运系统（Km = 0.2 mM，Vmax = 7.5 mmol h-1 g-1）受葡萄糖的抑制比受木糖的抑制更强。特异性较低的低亲和力转运系统（K = 50 mM，Vmax = 11 mmol h-1 g-1）似乎通过易化扩散机制起作用，并且组成性表达。抑制实验表明葡萄糖是两种木糖转运系统的底物。
Zotero 插件