Wahlstedt V, Gräsbeck R
J Lab Clin Med. 1985 Oct;106(4):439-46.
The urinary cobalamin (Cbl) binders were examined by gel filtration of concentrated urine on Sephadex G-200, alone and together with immunoglobulins against human Cbl binders. The 11 urine specimens from 10 persons studied had a free Cbl-binding capacity of 0.76 to 30.0 pmol/L (mean 6.6 pmol/L). Gel filtration with buffer preventing association of the Cbl binders gave peaks with elution volumes characteristic of serum transcobalamin and haptocorrin. When concentrated urine specimens were run together with immunoglobulins, the findings confirmed the presence of haptocorrin and transcobalamin and, in addition, of intrinsic factor. The presence of intrinsic factor was confirmed by incubating urine with an ion exchanger gel and by showing that an eluate of the gel reacted with the corresponding immunoglobulin. Part of the urinary intrinsic factor detected by radioimmunoassay was able to bind 57Co-Cbl; the rest appeared to be saturated with endogenous Cbl and possibly partly incapable of binding Cbl. All the free Cbl-binding capacity of urine concentrate could be blocked with adenine cyanocobamide, but only half with cobinamide; cobinamide blocked all the urinary haptocorrin but only part of the transcobalamin and none of the intrinsic factor eluted from the ion exchanger gel.
通过在葡聚糖凝胶G - 200上对浓缩尿液进行凝胶过滤，单独以及与抗人钴胺素结合蛋白的免疫球蛋白一起，对尿液中的钴胺素（Cbl）结合蛋白进行了检测。研究的10个人的11份尿液标本的游离Cbl结合能力为0.76至30.0 pmol/L（平均6.6 pmol/L）。用防止Cbl结合蛋白缔合的缓冲液进行凝胶过滤，得到了具有血清转钴胺素和运钴胺素蛋白洗脱体积特征的峰。当浓缩尿液标本与免疫球蛋白一起进行检测时，结果证实了运钴胺素蛋白和转钴胺素的存在，此外还证实了内因子的存在。通过将尿液与离子交换剂凝胶孵育，并表明凝胶的洗脱液与相应的免疫球蛋白发生反应，证实了内因子的存在。通过放射免疫测定法检测到的部分尿液内因子能够结合57Co - Cbl；其余部分似乎被内源性Cbl饱和，可能部分无法结合Cbl。尿浓缩物的所有游离Cbl结合能力都可以被氰钴胺素阻断，但用腺苷钴胺素只能阻断一半；腺苷钴胺素阻断了所有尿液中的运钴胺素蛋白，但只阻断了部分转钴胺素，对从离子交换剂凝胶上洗脱的内因子则没有阻断作用。
