STIMULATION OF PARTIALLY PURIFIED ADENYLATE-CYCLASE FROM BULL SPERM BY BICARBONATE
STIMULATION OF PARTIALLY PURIFIED ADENYLATE-CYCLASE FROM BULL SPERM BY BICARBONATE
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DOI：
10.1016/0014-5793(87)81036-0
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发表时间：
1987-06-22
期刊：
影响因子：
3.5
通讯作者：
SALOMON, Y
中科院分区：
文献类型：
--
作者：
GARTY, NB;SALOMON, Y
发现来自公牛精子的溶解和部分纯化的腺苷酸环化酶被碳酸氢钠 (NaHCO3) 特异性激活（高达 6 倍），并且在较小程度上被 NANO3 激活。其他钠盐要么无效（例如 NaCOOH），要么具有抑制作用（例如 NaHSO3、NaHSO4 和 Na2B4O7）。 NaHCO3 的刺激作用在 0-40 mM 范围内呈剂量依赖性，并且在镁存在的情况下测定酶活性时，与锰离子相比，刺激作用更大。碳酸氢盐似乎会影响最大酶速度 (Vmax)，但对 Mn-ATP 腺苷酸环化酶的 Km 没有影响。 NaHCO3 对腺苷酸环化酶的刺激与 DEAE-纤维素色谱或 BioGel P-100 凝胶过滤后记录的酶洗脱模式一致。这些结果表明，在刺激精子腺苷酸环化酶的过程中，碳酸氢盐很可能直接与该酶相互作用。此外，精子腺苷酸环化酶的这种内在和独特的性质可以解释其他人报道的关于在完整和破碎的精子制剂中碳酸氢盐刺激cAMP产生的结果，并提出与高碳酸氢盐浓度相关的增强精子活力的生化基础。
Solubilized and partially purified adenylate cyclase from bull sperm was found to be specifically activated (up to 6‐fold) by sodium bicarbonate (NaHCO3) and to a lesser extent by NANO3. Other sodium salts were either ineffective (e.g. NaCOOH) or inhibitory (e.g. NaHSO3, NaHSO4and Na2B4O7). Stimulation by NaHCO3was dose‐dependent in the range of 0–40 mM and was greater when enzyme activity was assayed in the presence of magnesium as compared with manganese ions. Bicarbonate seems to affect maximal enzyme velocity (Vmax) and has no effect on theKmof adenylate cyclase for Mn‐ATP. Stimulation of adenylate cyclase by NaHCO3coincided with the elution pattern of the enzyme as recorded following chromatography on DEAE‐cellulose or gel filtration on BioGel P‐100. These results suggest that in the course of stimulation of sperm adenylate cyclase, bicarbonate is likely to interact directly with the enzyme. Furthermore, this intrinsic and unique property of sperm adenylate cyclase may explain results reported by others on the stimulation of cAMP production by bicarbonate in intact and broken sperm preparations and suggest a biochemical basis for enhanced sperm motility associated with high bicarbonate concentrations.