Olsson H, Martínez-Arias W, Jergil B
Biochemistry, Chemical Centre, University of Lund, Sweden.
FEBS Lett. 1993 Aug 2;327(3):332-6. doi: 10.1016/0014-5793(93)81015-r.
A PtdIns 4-kinase was purified extensively from rat liver exocytotic vesicles. The enzyme had a low Km for ATP, was inhibited by adenosine, and had an apparent molecular mass of 54 kDa, indicating it to be a type II PtdIns-kinase. The activity of the purified enzyme was enhanced several-fold by PtdCho, and to some extent by other phospholipids with basic polar head groups, and was inhibited by PtdSer. Kinetic analyses, presenting the substrate in mixed micelles of Triton X-100, PtdIns and PtdCho, showed that the effect of PtdCho was both to increase Vmax and to decrease the apparent Km for micellar PtdIns.
一种磷脂酰肌醇4-激酶从大鼠肝脏胞吐小泡中被大量纯化出来。该酶对ATP的米氏常数较低，被腺苷抑制，表观分子量为54 kDa，表明它是一种II型磷脂酰肌醇激酶。纯化酶的活性被磷脂酰胆碱提高了几倍，并在一定程度上被其他带有碱性极性头部基团的磷脂提高，而被磷脂酰丝氨酸抑制。动力学分析表明，将底物呈现在Triton X-100、磷脂酰肌醇和磷脂酰胆碱的混合胶束中时，磷脂酰胆碱的作用是增加最大反应速度并降低胶束状磷脂酰肌醇的表观米氏常数。
