Lowendorf H S, Bazinet G F, Slayman C W
Biochim Biophys Acta. 1975 May 21;389(3):541-9. doi: 10.1016/0005-2736(75)90164-9.
In addition to the constitutive, low-affinity phosphate-transport system described previously, Neurospora possesses a second, high-affinity system which is derepressed during phosphorus starvation. At pH 5.8, System ii has a K1/2 of about 3muM and a Jmax of 5.2 mmol/1 cell water per min. System ii reaches maximal activity after about 2 h of growth in phosphorus-free minimal medium. Its formation is blocked by cycloheximide and, once made, it appears to turn over rapidly. Addition of cycloheximide to fully derepressed cultures results in the decay of System ii with a t1/2 of 14 min, very similar to the turnoacteriol. 95, 959-966) for tryptophan transport in Neurospora. Thus, these transport systems appear to be regulated by a balance between synthesis and breakdown, as affected by intracellular pools of substrate or related compounds.
除了之前描述的组成型低亲和力磷酸盐转运系统外，粗糙脉孢菌还拥有第二种高亲和力系统，该系统在磷饥饿期间会去阻遏。在pH 5.8时，系统ii的K1/2约为3μM，Jmax为每分钟5.2 mmol/1细胞水。在无磷基本培养基中生长约2小时后，系统ii达到最大活性。其形成被环己酰亚胺阻断，一旦形成，它似乎会迅速周转。向完全去阻遏的培养物中添加环己酰亚胺会导致系统ii以14分钟的半衰期衰减，这与粗糙脉孢菌中色氨酸转运的周转特征非常相似（参考文献95, 959 - 966）。因此，这些转运系统似乎受底物或相关化合物的细胞内库影响，通过合成与分解之间的平衡来调节。
