Disclosed herein are methods for preparing modified, functional conjugates that includes the steps as follows. First, biotinylated peptides, each having a His–tag sequence, are gradually added into avidin–like molecules in a molar ratio between 1:4 to 16:1 so as to form a plurality of avidin–biotin–peptide conjugates with different valence states. The avidin–biotin–peptide conjugates are then separated using a nickel affinity column eluted with an imidazole gradient to produce a first eluate including mostly first single–valent avidin–biotin–peptide conjugates each having a first valence. The first single–valent avidin–biotin–peptide conjugates are then mixed with functional molecules under conditions allowing the formation of functional molecules modified with the first single–valent biotin–binding peptides of the first valence. Methods for preparing single–valent, modified avidin–like molecules are also disclosed herein.本案揭示用以製備經修飾功能性複合物的方法。首先,慢慢地將莫耳比為1:4至16:1的經生物素標記的胜肽加入至卵白素類粒子中,以形成但有不同價數的複數個卵白素類–生物素–胜肽複合物,其中每一經生物素標記的胜肽包含一組胺酸標籤序列。之後,利用鎳親和性管柱並以咪唑濃度梯度洗提卵白素類–生物素–胜肽複合物,以得到主要由具有第一價數的第一單一價數卵白素類–生物素–胜肽複合物所構成的第一洗提物。接著,將第一單一價數卵白素類–生物素–胜肽複合物與功能性粒子在適當條件下混合,以形成經帶有第一價數之第一單一價數生物素–結合胜肽修飾的功能性粒子。此處亦揭示了用以製備單一價數經修飾卵白素類粒子的方法。
