Streptavidin sulfo-SMCC

The following protocol describes the activation of avidin or streptavidin with sulfo-SMCC and its subsequent conjugation with an enzyme modified to contain sulfhydryls using SATA (Chapter 1, Section 4.1). A method for the opposite approach, wherein the enzyme is activated with SMCC and the avidin component is thiolated, is presented immediately after this protocol. This strategy may be the most common approach to forming these conjugates (Fig. 363). In addition, since there are enzymes commercially available that are preactivated with SMCC (Pierce), their use may be the easiest solution. 

Add 1 mg of sulfo-SMCC (Pierce) to each milliliter of avidin or streptavidin solution. Mix to dissolve. 

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