Use of genetically prepared enzyme conjugates in lactose and galactose analyses.

Genetically prepared enzyme conjugates were used in soluble enzyme assays for determination of lactose and galactose with spectrophotometric, fluorimetric, and bioluminometric detection. The use of a bifunctional enzyme in biosensors based on calorimetric detection is also presented. Due to proximity of the enzymes to one another several advantages in the analyses were achieved.

Construction and characterization of a recombinant tripartite enzyme, galactose dehydrogenase/beta-galactosidase/galactokinase.

The in-frame gene fusion between 3 enzymes, galactose dehydrogenase, beta-galactosidase and galactokinase, is described. The purified artificial tripartite enzyme displayed all three enzymic activities. Two major forms of the hybrid protein were found, consisting of 4 and 8 subunits respectively, but other forms could also be identified.

Construction of an artificial bifunctional enzyme, beta-galactosidase/galactose dehydrogenase, exhibiting efficient galactose channeling.

The in-frame fusion between two oligomeric enzymes, beta-galactosidase and galactose dehydrogenase, is described. The lacZ gene was fused to the 3' end of the galdh gene with a linker encoding only three amino acids. The purified artificial bifunctional enzyme displayed the enzymic activity of both gene products.