Synthesis and characterization of a carbene-generating biotinylated lactosylceramide analog as a novel chromogenic photoprobe for GM3 synthase

Abstract

A new biotinylated lactose derivative bearing a nitro-substituted chromogenic diazirine was synthesized. The biotinyl group within the structure enabled the performance of a convenient assay of GM3 synthase based on avidin-biotin technology, and the K(m) values of this biotinylated photoprobe were determined as 40 and 47 μM using bovine brain and rat liver Golgi as enzyme sources, respectively. Furthermore, the sialylation of lactosylceramide, a natural acceptor substrate for GM3 synthase, was competitively inhibited by this synthetic analog. The reagent could be a useful chromogenic photoprobe for GM3 synthase.