Biotinyl- 6-aminoquinoline

Wastell H, Dale G, Bartlett (1984) A sensitive rate assay for biotinidase using a new derivative of biotin, biotinyl-6-aminoquinoline. Anal Biochem 140 69-73... 

Biotinidase hydrolytically cleaves biocytin to produce biotin and lysine. This assay uses a fluorimetric substrate, biotinyl-6-aminoquinoline (BAQ), and is suitable for use with samples such as milk and serum without pretreatment or dialysis. 

The reaction mixture contained 45 fiL of substrate solution (0.044 mM biotinyl-6-aminoquinoline dissolved in 0.1 M phosphate buffer (pH 7.0) containing 1 mM Na4EDTA and 10 mM 2-mercaptoethanol, and 5 /u.L of enzyme solution. The reaction was allowed to proceed for an appropriate time at 37°C before being stopped by the addition of 0.10 mL of methanol. After centrifugation, 10 /.iL of the supernate was injected into the HPLC system. After a lag period during the first 5 minutes, product information was linear with time for the next 20 minutes. The reaction was linear with amounts of human serum up to 100 /u,L (total reaction volume of 0.5 mL) when incubated for 60 minutes. 

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