Biotin is a small biomolecule important for many cellular processes. Most importantly for biotechnology applications, biotin is ammenable to conjugation to proteins for use in biochemical assays. Biotin has a very strong affinity for avidin and streptavidin, an attraction that is the strongest and most stable non-covalent interaction known. Beta-galactosidase (beta-gal, beta-gal) is an enzyme that hydrolyzes beta-galactosides (such as lactose and various glycoproteins) into simple sugars. Beta-galactosidase is routinely used as a reporter in biochemical experiments as well as a marker for gene expression experiments in E. coli. Beta-galactosidase can be used to cleave the chemical X-gal that forms an intense blue product that can easily be quantified.
