Rose M, Entian K D, Hofmann L, Vogel R F, Mecke D
Medizinisch-Naturwissenschaftliches Forschungszentrum, Universität Tübingen, FRG.
FEBS Lett. 1988 Dec 5;241(1-2):55-9. doi: 10.1016/0014-5793(88)81030-5.
The fructose-1,6-bisphosphatase gene was used with multicopy plasmids to study rapid reversible and irreversible inactivation after addition of glucose to derepressed Saccharomyces cerevisiae cells. Both inactivation systems could inactivate the enzyme, even if 20-fold over-expressed. The putative serine residue, at which fructose-1,6-bisphosphatase is phosphorylated, was changed to an alanine residue without notably affecting the catalytic activity. No rapid reversible inactivation was observed with the mutated enzyme. Nonetheless, the modified enzyme was still irreversibly inactivated, clearly demonstrating that phosphorylation is an independent regulatory circuit that reduces fructose-1,6-bisphosphatase activity within seconds. Furthermore, irreversible glucose inactivation was not triggered by phosphorylation of the enzyme.
果糖-1,6-二磷酸酶基因与多拷贝质粒一起用于研究向去阻遏的酿酒酵母细胞中添加葡萄糖后快速可逆和不可逆的失活情况。即使该酶过表达20倍，这两种失活系统仍能使其失活。推测的果糖-1,6-二磷酸酶被磷酸化的丝氨酸残基被改变为丙氨酸残基，而对催化活性没有明显影响。突变酶未观察到快速可逆失活。尽管如此，修饰后的酶仍会不可逆地失活，这清楚地表明磷酸化是一个独立的调节回路，可在数秒内降低果糖-1,6-二磷酸酶的活性。此外，酶的磷酸化不会引发不可逆的葡萄糖失活。
