Adrian G S, Keenan R W
Biochim Biophys Acta. 1979 Dec 18;575(3):431-8. doi: 10.1016/0005-2760(79)90112-7.
Tetrahymena pyriformis contains an enzyme which hydrolyzed dolichyl phosphate. This activity was solubilized from lyophilized samples of this organism and was relatively stable when stored frozen. The soluble enzyme preparation had an acid pH optimum and hydrolyzed both dolichyl and phytanyl phosphates at equivalent rates. The polyprenylphosphate phosphatase activity was compared with the acid phosphatases which hydrolyzed p-nitrophenyl phosphate and marked differences were found. Dolichyl phosphate hydrolysis required Mg2+ for maximum activity while the bulk of the phosphatase activity was not effected by the absence of this ion. Other differences were that the polyprenylphosphate phosphatase was relatively insensitive to inhibitors such as tartrate and vanadium oxide sulfate which had a pronounced effect on the rate of p-nitrophenyl phosphate hydrolysis. The two activities also appeared to have different subcellular distributions. The polyprenylphosphate phosphatase was markedly inhibited by ethoxy formic anhydride, a reagent which is active against enzymes containing a histidine residue at their active site, while p-nitrophenyl phosphate hydrolysis was unaffected. The polyprenylphosphate phosphatase may be important in regulating the level of dolichyl phosphate in T. pyriformis and thus the rate of glycoprotein synthesis. It is also a useful tool which is capable of liberating dolichol from dolichyl phosphate under mild conditions which will permit the further characterization of the polyprenols.
梨形四膜虫含有一种能水解磷酸多萜醇的酶。这种活性是从该生物体的冻干样品中溶解出来的，冷冻保存时相对稳定。可溶性酶制剂的最适pH值呈酸性，能以相同速率水解磷酸多萜醇和磷酸植烷醇。将聚异戊二烯磷酸磷酸酶活性与水解对硝基苯磷酸的酸性磷酸酶进行比较，发现了显著差异。水解磷酸多萜醇需要Mg2+才能达到最大活性，而大部分磷酸酶活性不受该离子缺失的影响。其他差异在于，聚异戊二烯磷酸磷酸酶对酒石酸盐和硫酸钒氧化物等抑制剂相对不敏感，而这些抑制剂对水解对硝基苯磷酸的速率有显著影响。这两种活性似乎也有不同的亚细胞分布。聚异戊二烯磷酸磷酸酶受到乙氧基甲酸酐的显著抑制，乙氧基甲酸酐这种试剂对活性位点含有组氨酸残基的酶有作用，而水解对硝基苯磷酸不受影响。聚异戊二烯磷酸磷酸酶可能在调节梨形四膜虫中磷酸多萜醇的水平以及糖蛋白合成速率方面很重要。它也是一种有用的工具，能够在温和条件下从磷酸多萜醇中释放出多萜醇，这将有助于对多萜醇进行进一步表征。
