Mahrenholz A M, Hefta S A, Mansour T E
Department of Pharmacology, Stanford University School of Medicine, California 94305.
Arch Biochem Biophys. 1991 Aug 1;288(2):463-7. doi: 10.1016/0003-9861(91)90221-4.
We have reported previously that phosphofructokinase from the liver fluke Fasciola hepatica is activated by phosphorylation with cAMP-dependent protein kinase, and that this event appears to be important in vivo for regulation of PFK (E. S. Kamemoto, L. Lan, and T. E. Mansour (1989) Arch. Biochem. Biophys. 271, 553-559). Here, we report the amino acid sequence of the single tryptic phosphopeptide generated after phosphorylation of the purified enzyme with cAMP-dependent protein kinase and [gamma 32P]ATP. Through a combination of Edman microsequence analysis, fast atom bombardment mass spectroscopy, and phosphoamino acid analysis, the sequence of the phosphorylated peptide was determined to be: R-S-T(P)-M-M-I-P-G-M-E-G-K. This sequence is not homologous to any previously determined phosphofructokinase phosphopeptides. Regulatory differences between the mammalian and parasite enzymes are discussed with particular emphasis on regulation by protein phosphorylation.
我们之前报道过，来自肝片吸虫（Fasciola hepatica）的磷酸果糖激酶可被依赖于cAMP的蛋白激酶磷酸化激活，而且这一事件在体内对于磷酸果糖激酶（PFK）的调节似乎很重要（E.S. 卡门托、L. 兰和T.E. 曼苏尔（1989年）《生物化学与生物物理学文献》271卷，553 - 559页）。在此，我们报告用依赖于cAMP的蛋白激酶和[γ-32P]ATP对纯化的酶进行磷酸化后产生的单一胰蛋白酶磷酸肽的氨基酸序列。通过埃德曼微量序列分析、快原子轰击质谱分析和磷酸氨基酸分析相结合的方法，确定磷酸化肽的序列为：R - S - T(P) - M - M - I - P - G - M - E - G - K。该序列与之前确定的任何磷酸果糖激酶磷酸肽均无同源性。文中讨论了哺乳动物和寄生虫酶之间的调节差异，特别强调了蛋白磷酸化调节。
