A specific binding assay for determining a ligand in a liquid medium employing an organic prosthetic group residue, such as a residue of flavin adenine dinucleotide, flavin mononucleotide, or heme, as a label component in the labeled conjugate. Preferably, the label component is the prosthetic group residue alone or is a holoenzyme residue comprising such prosthetic group residue combined with an apoenzyme in the form of a holoenzyme complex. In the former case, the label component preferably is monitored in the assay by adding an apoenzyme after the binding reaction has been initiated and measuring the resultant holoenzyme activity. In the latter case, the label component is monitored simply by measuring holoenzyme activity. The assay method may follow conventional homogeneous and heterogeneous schemes. Preferred apoenzymes for use in the assay are apoglucose oxidase and apoperoxidase. The assay offers the advantages of colorimetric read-out and of being readily adaptable to automated techniques. Also disclosed are prosthetic group-labeled and enzyme-labeled conjugates for use in the assay, as well as a method for preparing the latter conjugates.
一种特定的结合测定法,用于在液态介质中确定
配体,利用有机假体基残基作为标记组分的标记共轭物,例如黄素
腺嘌呤二核苷酸、黄素单核苷酸或血红素残基。优选地,标记组分是假体基残基单独存在或是由这样的假体基残基与一个原酶组成的全酶残基组合而成的全酶复合物。在前一种情况下,标记组分最好是在结合反应开始后加入原酶,并测量所得到的全酶活性来监测结合反应。在后一种情况下,标记组分仅通过测量全酶活性来监测。测定方法可以遵循常规的均相和非均相方案。用于测定的优选原酶是去
葡萄糖氧化酶和去
过氧化酶。该测定方法具有色度读出和易于自动化技术适应的优点。还公开了用于测定的假体基标记和酶标记共轭物,以及制备后者共轭物的方法。