Toll J B, Andersson R G
Allergy. 1984 Oct;39(7):515-20. doi: 10.1111/j.1398-9995.1984.tb00872.x.
Extracts from purified human basophils revealed activity of cAMP-phosphodiesterase with a km-value of 0.59 microM. The enzyme was not activated by Ca-ions. Enprofylline and theophylline inhibited the enzyme in a competitive manner. Enprofylline was more potent than theophylline. These drugs did also inhibit the anti-IgE-induced histamine release from the basophils. These results favour the hypothesis that inhibition of histamine release of enprofylline is caused by an inhibition of phosphodiesterase. Although accumulating data have indicated that theophylline, at therapeutic concentrations, is a weak inhibitor of cAMP-phosphodiesterase activity, there is reason to believe that enprofylline, at therapeutic concentrations, may act at least partly as a phosphodiesterase inhibitor.
从纯化的人嗜碱性粒细胞提取物中发现了cAMP - 磷酸二酯酶的活性，其Km值为0.59微摩尔。该酶未被钙离子激活。恩丙茶碱和茶碱以竞争性方式抑制该酶。恩丙茶碱比茶碱更有效。这些药物也抑制了抗IgE诱导的嗜碱性粒细胞组胺释放。这些结果支持了恩丙茶碱抑制组胺释放是由磷酸二酯酶抑制引起的这一假说。尽管越来越多的数据表明，在治疗浓度下，茶碱是cAMP - 磷酸二酯酶活性的弱抑制剂，但有理由相信，在治疗浓度下，恩丙茶碱可能至少部分作为磷酸二酯酶抑制剂起作用。
