Nakazawa K, Kitajima S
Biochim Biophys Acta. 1980 Mar 14;612(1):171-7. doi: 10.1016/0005-2744(80)90290-9.
A guanylate cyclase preparation partially purified from supernatant of a pig lung extract was subjected to affinity chromatography on an Agarose-GTP column. The major portion of the cyclase activity was adsorbed on the column and then eluted with 50 mM EDTA and 0.5 M KCl, whereas the fractions non-adsorbed on the column contained a factor which enhanced the cyclase activity. Addition of the activating factor to a cyclase reaction mixture increase the enzyme activity without a time lag, and this enhancement by the factor was dose-dependent. With concomitant presence of cyclase and the factor in the reaction mixture the apparent Km value for GTP-Mn2+ of the enzyme was 56 microM, this value being the same as in absence of the factor, however, here the maximum velocity increased 4-fold. The factor was nondiffusable, heat-labile, partially sensitive to trypsin, and resistant to acid or alkali. As estimated by gel filtration, this factor had an apparent molecular weight of 85 000.
从猪肺提取物上清液中部分纯化得到的鸟苷酸环化酶制剂，在琼脂糖 - GTP柱上进行亲和层析。环化酶活性的主要部分被吸附在柱上，然后用50 mM EDTA和0.5 M KCl洗脱，而未吸附在柱上的组分含有一种能增强环化酶活性的因子。向环化酶反应混合物中添加激活因子可立即增加酶活性，且该因子的这种增强作用呈剂量依赖性。在反应混合物中同时存在环化酶和该因子时，该酶对GTP - Mn2+的表观Km值为56 microM，此值与不存在该因子时相同，然而，此时最大反应速度增加了4倍。该因子不可扩散、对热不稳定、对胰蛋白酶部分敏感，且耐酸或耐碱。通过凝胶过滤估计，该因子的表观分子量为85000。
