Sharma R K, Tan Y, Raju R V
Department of Pathology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Arch Biochem Biophys. 1997 Mar 1;339(1):40-6. doi: 10.1006/abbi.1996.9837.
Calmodulin-dependent cyclic nucleotide phosphodiesterase was identified in and purified to apparent homogeneity from the total calmodulin-binding protein fraction of bovine eye in a single step by immunoaffinity chromatography. The bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase is immunologically similar to the bovine brain 60-kDa isozyme. The purified enzyme had higher affinity for calmodulin than the 60-kDa phosphodiesterase isozyme from bovine brain, but similar affinity to that of the heart isozyme. When the Ca(2+)-dependence of the eye enzyme was compared to cardiac calmodulin-dependent cyclic nucleotide phosphodiesterase at an identical concentration of calmodulin, the bovine eye calmodulin-dependent cyclic nucleotide phosphodiesterase was activated at the same Ca2+ concentration as the bovine heart calmodulin-dependent cyclic nucleotide phosphodiesterase isozyme.
通过免疫亲和色谱法，在一步操作中从牛眼的总钙调蛋白结合蛋白组分中鉴定并纯化出钙调蛋白依赖性环核苷酸磷酸二酯酶，使其达到表观均一性。牛眼钙调蛋白依赖性环核苷酸磷酸二酯酶在免疫学上与牛脑60 kDa同工酶相似。纯化后的酶对钙调蛋白的亲和力高于来自牛脑的60 kDa磷酸二酯酶同工酶，但与心脏同工酶的亲和力相似。当在相同浓度的钙调蛋白下比较眼酶的Ca(2+)依赖性与心脏钙调蛋白依赖性环核苷酸磷酸二酯酶时，牛眼钙调蛋白依赖性环核苷酸磷酸二酯酶在与牛心脏钙调蛋白依赖性环核苷酸磷酸二酯酶同工酶相同的Ca2+浓度下被激活。
