Methotrexate-labeled iodothyronine conjugates useful as labeled conjugates in specific binding assays (e.g., homogeneous immunoassays) for determining iodothyronines, particularly thyroxine and triiodothyronine, or for determining iodothyronine uptake in liquid samples. The methotrexate label is monitored preferably by measuring its inhibitory effect on the enzyme dihydrofolate reductase. Also provided are assay methods, reagent means, test kits and test devices for determining an iodothyronine, comprising the methotrexate-labeled conjugate, a binding protein (e.g., antibody) for the iodothyronine, dihydrofolate reductase, and an indicator of dihydrofolate reductase activity, and for determining iodothyronine uptake, comprising the labeled conjugate, binding protein, dihydrofolate reductase, and enzyme indicator.
甲氨蝶呤标记的
碘甲腺原
氨酸轭合物可作为标记轭合物用于特异性结合测定(如均相免疫测定),以确定
碘甲腺原
氨酸,特别是
甲状腺素和三
碘甲腺原
氨酸,或确定液体样品中
碘甲腺原
氨酸的吸收。
甲氨蝶呤标签最好通过测量其对二氢叶酸还原酶的抑制作用来监测。还提供了测定
碘甲腺原
氨酸的检测方法、试剂手段、检测试剂盒和检测装置,包括
甲氨蝶呤标记的共轭物、
碘甲腺原
氨酸的结合蛋白(如
抗体)、二氢叶酸还原酶和二氢叶酸还原酶活性指示剂,以及测定
碘甲腺原
氨酸吸收的检测方法、试剂手段、检测试剂盒和检测装置,包括标记的共轭物、结合蛋白、二氢叶酸还原酶和酶指示剂。