Schmidt J A, Stirling J L
Biochem J. 1982 Aug 15;206(2):185-93. doi: 10.1042/bj2060185.
When cells of the slime mould Dictyostelium discoideum are allowed to starve in the presence of alpha-chymotrypsin, they are blocked in development at the stage where tight aggregates form tips. Analysis of developmentally regulated enzymes has shown that alpha-mannosidase, beta-N-acetylglucosaminidase, threonine deaminase, tyrosine aminotransferase, beta-glucosidase and the carbohydrate-binding protein discoidin are unaffected, but enzymes that show an increase in specific activity during post-aggregative development, namely glycogen phosphorylase, UDP-glucose pyrophosphorylase, UDP-galactose 4-epimerase, UDP-galactose polysaccharide transferase and alkaline phosphatase, did not show the characteristic increase when development was blocked by alpha-chymotrypsin. Recovery of cells from the effects of alpha-chymotrypsin was accompanied by the formation of fruiting bodies and a concomitant increase in the specific activity of UDP-glucose pyrophosphorylase. Uptake or efflux of 45Ca2+ was not altered in the presence of alpha-chymotrypsin. Cells allowed to develop in alpha-chymotrypsin, or treated with the enzyme for 15 min, had a markedly reduced ability to bind cyclic AMP with low affinity; high-affinity binding was unaffected. Pronase had a similar effect on cyclic AMP binding, but trypsin, which does not alter developmental processes, has no effect on cyclic AMP binding to D. discoideum cells.
当让盘基网柄菌这种黏菌的细胞在α-胰凝乳蛋白酶存在的情况下饥饿时，它们在发育过程中会在紧密聚集体形成尖端的阶段受阻。对发育调控酶的分析表明，α-甘露糖苷酶、β-N-乙酰葡糖胺酶、苏氨酸脱氨酶、酪氨酸转氨酶、β-葡糖苷酶和碳水化合物结合蛋白盘基网柄菌素不受影响，但在聚集后发育过程中比活性增加的酶，即糖原磷酸化酶、UDP-葡萄糖焦磷酸化酶、UDP-半乳糖4-差向异构酶、UDP-半乳糖多糖转移酶和碱性磷酸酶，在发育被α-胰凝乳蛋白酶阻断时并未表现出特征性的增加。从α-胰凝乳蛋白酶的影响中恢复的细胞伴随着子实体的形成以及UDP-葡萄糖焦磷酸化酶比活性的相应增加。在α-胰凝乳蛋白酶存在的情况下，45Ca2+的摄取或流出没有改变。在α-胰凝乳蛋白酶中发育或用该酶处理15分钟的细胞，以低亲和力结合环磷酸腺苷（cAMP）的能力明显降低；高亲和力结合不受影响。链霉蛋白酶对cAMP结合有类似的影响，但不改变发育过程的胰蛋白酶对盘基网柄菌细胞结合cAMP没有影响。
