Voskoboev A I, Ostrovskii Iu M, Grishchenko E A, Averin V A
Vopr Med Khim. 1981 Sep-Oct;27(5):690-4.
Protein-bound and free forms of thiamin diphosphate (TDP) (separated by dialysis and gel filtration) were found in rat erythrocytes. Content of TDP in blood did not correlate with the transketolase activity at the initial steps of B1 avitaminosis. Decrease of the DTP total amount in blood by more than 80% did not affect distinctly the transketolase activity. As shown by binding of 14C-TDP during the equilibrium dialysis and gel filtration, the apotransketolase did not occur in erythrocytes of thiamin-deficient rats. Activation of transketolase, which occurred after addition of 50 mg TDP into the whole blood lysates (TDP-effect), was characteristic for the later steps of the avitaminosis; it depended rather on leukocyte than on erythrocyte transketolase. Estimation of TDP concentration in blood was the most suitable assay for a body providing with thiamin at the early steps of the avitaminosis. The accuracy of the coenzyme estimation was decreased within 15-30 days of the avitaminosis due to its drastic lowering. In this case, determination of the transketolase activity was the most suitable criterion. The thiamin-binding protein, found in erythrocytes, appears to participate in transport of the vitamin across erythrocyte membranes.
在大鼠红细胞中发现了硫胺素二磷酸（TDP）的蛋白结合形式和游离形式（通过透析和凝胶过滤分离）。在维生素B1缺乏症初期，血液中TDP的含量与转酮醇酶活性不相关。血液中DTP总量减少80%以上对转酮醇酶活性没有明显影响。通过平衡透析和凝胶过滤过程中14C-TDP的结合表明，硫胺素缺乏大鼠的红细胞中不存在脱辅基转酮醇酶。在全血裂解物中加入50 mg TDP后发生的转酮醇酶激活（TDP效应）是维生素缺乏症后期的特征；它更多地取决于白细胞而非红细胞转酮醇酶。在维生素缺乏症初期，测定血液中TDP浓度是评估机体硫胺素供应情况的最合适检测方法。由于维生素严重降低，在维生素缺乏症的15 - 30天内辅酶估计的准确性会下降。在这种情况下，测定转酮醇酶活性是最合适的标准。在红细胞中发现的硫胺素结合蛋白似乎参与了维生素跨红细胞膜的转运。
