Preller A, Guixé V, Kessi E, Ureta T
Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago.
Arch Biochem Biophys. 1995 Jan 10;316(1):555-60. doi: 10.1006/abbi.1995.1074.
The characterization of fructose-1,6-bisphosphatase in stage VI oocytes from the frog Caudiverbera caudiverbera, as well as the in vivo activity, is reported. The enzyme has a subunit molecular weight of approximately 43,500, has an apparent Km value of 17 microM for fructose-1,6-bisP, and is inhibited by substrate concentrations beyond 100 microM. AMP and fructose-2,6-bisP are strong inhibitors of oocyte fructose-1,6-bisphosphatase activity with Ki values of 9 and 2 microM respectively. Inhibition by AMP is cooperative with a nH value of 2.2. In vivo fructose-1,6-bisphosphatase activity was demonstrated by microinjection of [U-14C]- or [6-32P]fructose-1,6-bisP and subsequent chromatographic separation and identification of labeled products. The relevance of these findings for the metabolism of glucose in frog oocytes is discussed.
本文报道了来自尾蛙（Caudiverbera caudiverbera）第VI期卵母细胞中果糖-1,6-二磷酸酶的特性及其体内活性。该酶的亚基分子量约为43,500，对果糖-1,6-二磷酸的表观Km值为17μM，且在底物浓度超过100μM时受到抑制。AMP和果糖-2,6-二磷酸是卵母细胞果糖-1,6-二磷酸酶活性的强抑制剂，其Ki值分别为9μM和2μM。AMP的抑制作用具有协同性，nH值为2.2。通过显微注射[U-14C]-或[6-32P]果糖-1,6-二磷酸，随后进行色谱分离和标记产物鉴定，证明了体内果糖-1,6-二磷酸酶的活性。本文还讨论了这些发现与蛙卵母细胞中葡萄糖代谢的相关性。
