Enzyme Activity Measurements Using Bio-Layer Interferometry

Abstract

Disclosed are enzyme assays using biolayer interferometry. Assays may be carried out using immobilized substrate or with a substrate capture format. In certain embodiments, the assays are carried out using unlabeled substrates. The methods are broadly applicable to enzyme assay measurements, can be carried out in vivo or in vitro, and are easily multiplexed.

1 . An assembly, comprising an optical element adapted for coupling to a light source via an optical fiber, the optical element including (a) a proximal reflecting surface and a distal reflecting surface separated by at least 50 nm, and (b) a layer of enzyme substrate molecules positioned so that interference between a reflected beam from the proximal reflecting surface and a reflected beam from the distal reflecting surface varies as an enzyme reacts with the substrate. 
   
   
       2 . An assembly, comprising an optical element adapted for coupling to a light source via an optical fiber, the optical element including (a) a proximal reflecting surface and a distal reflecting surface separated by at least 50 nm, and (b) a layer of analyte binding molecules positioned so that interference between a reflected beam from the proximal reflecting surface and a reflected beam from the distal reflecting surface varies as an enzyme reacts with the substrate. 
   
   
       3 . A kit, comprising a glass fiber adapted for coupling to a bio-layer interferometer, reagents and instructions for derivatizing the glass fiber with a substrate layer or an analyte binding molecular layer. 
   
   
       4 . The kit of  claim 3 , further comprising reagents and instructions for optically activating an end of the glass fiber.