6-bromoacetyl-2-dimethylaminonaphthalene and Diabetes-Mellitus

We synthesized mutants of glucose/galactose-binding protein (GBP), labeled with the environmentally sensitive fluorophore Badan, with the aim of producing a fluorescence-based glucose sensing system with an operating range compatible with continuous glucose monitoring in patients with diabetes mellitus. From five mutants tested, the triple mutant H152C/A213R/L238S-Badan showed a large (200%) maximal increase in fluorescence intensity on the addition of glucose, with a binding constant (K(d)) of 11 mM, an operating range of approximately 1-100 mM, and similar responses in buffer and serum. The mean fluorescence lifetime of this mutant also increased by 70% on the addition of glucose. We conclude that the GBP mutant H152C/A213R/L238S, when labeled with Badan, is suitable for development as a robust sensor for in vivo glucose monitoring in diabetes.

Topics: 2-Naphthylamine; Amino Acid Substitution; Biosensing Techniques; Blood Glucose; Calcium-Binding Proteins; Diabetes Mellitus; Enzyme Assays; Fluorescent Dyes; Humans; Monosaccharide Transport Proteins; Mutagenesis, Site-Directed; Periplasmic Binding Proteins; Protein Isoforms