腺苷钴胺是维生素B12的一个系列产品,化学名称为5,6-二甲基苯并咪唑-5'-脱氧腺嘌呤核苷基钴胺,是一种八面体形的钴胺络合物。腺苷钴胺以暗红色结晶或非结晶性粉末形式存在,具有较强的吸湿性和对光敏感性。作为维生素B12的重要品种之一,它是一种原料药,拥有重要的医用价值。
生理功能腺苷钴胺是氰钴型维生素B12的类似物,参与细胞核苷酸的合成,同时也是甲基转换和叶酸代谢过程中的重要辅酶。具体来说,它可以促进甲基四氢叶酸的形成,并有助于三羧酸循环,对神经髓鞘中脂蛋白的生成至关重要。此外,腺苷钴胺还能维持巯基酶的活性状态,参与广泛的蛋白质及脂肪代谢。该物质能够促进红细胞的发育与成熟,对于完整形成神经鞘脊髓纤维和保持消化系统上皮细胞功能也极为重要。
用途腺苷钴胺主要用于治疗由于维生素B12缺乏引起的各种疾病,如妊娠期贫血、营养不良性贫血等。此外,它也可用于辅助治疗由放射线或药物引起的白细胞减少症及营养性疾病。
药物相互作用在使用时需要注意以下几点:
腺苷钴胺是一种红色针状结晶或结晶性粉末,没有气味和味道,并且具有吸湿性。其熔点大于300℃,210-220℃(颜色较深)时的熔点则略低;比旋光度为[α]23656 -59°(在水中),它在361nm波长下的吸收值最大。该物质可溶于水、乙醇和醋酸,但不溶于氯仿、乙醚或丙酮。腺苷钴胺的半数致死量(LD50)为1364 mg/kg(经腹腔注射给大鼠使用)。
用途在生化研究和组织培养中作为重要试剂,并且临床用于治疗各种巨幼细胞性贫血、营养不良性贫血等病症。腺苷钴胺属于维生素B族,参与体内核酸、胆碱及蛋氨酸的合成以及脂肪与糖类的代谢过程。
生产方法腺苷钴胺是通过生产金霉素或链霉素发酵液水解、氰化钠氰化、酸化并精制而成的一种维生素类药物。
The cobA gene of Salmonella typhimurium and its product were overexpressed to approximately 20% of the total cell protein. CobA was purified to 98% homogeneity; N-terminal sequence analysis (21 residues) of homogeneous protein confirmed the predicted amino acid sequence. ATP:corrinoid adenosyltransferase activity was demonstrated in vitro to be associated with CobA. This activity was optimal at pH 8 and 37 degrees C. A quantitative preference was determined for Mn(II) cations and ATP. The apparent Km of CobA for ATP was 2.8 microM, and that for cob(I)alamin was 5.2 microM. Vmax was measured at 0.43 nmol/min. Cobinamide served as the substrate for CobA to yield adenosylcobinamide. Activity was stable at 4 degrees C for several weeks but was lost rapidly at room temperature (50% overnight). Dithiothreitol was required to maintain the enzymatic activity of CobA.