p-Phenylene Diisothiocyanate-Based Covalent Immobilization of β-d-Galactosidase and Determination of Enzyme Activity by Cleavage of X-Gal and ONPG on Solid Support

Herein, we present the immobilization of a technical grade β-d-galactosidase on amino-functionalized microtiter plates. Afterward, we transferred the results to a resin-based approach. For the covalent binding of the enzyme, an amino-functionalized microtiter plate was prefunctionalized with 1,4-phenylendiisothiocyanate. The cleavage of the substrate 5-bromo-4-chloro-3-indoxyl-β-d-galactopyranoside (X-Gal) produces a deep blue dye, which was quantified in a microtiter plate reader at 595 nm. The maximum reaction rates and the Michaelis-Menten constant were calculated. In addition, the unwanted blue precipitate formed during the experiments could be minimized by optimizing the experiments. When transferring the immobilization method to Rink amide resin, o-nitrophenyl-β-d-galactopyranoside was used as the substrate and the measurement was carried out in a photometer at 420 nm.

Dairy Products and Health: Recent Insights

Milk, cheese, yogurt, and other dairy products have long been known to provide good nutrition. Major healthful contributors to the diets of many people include the protein, minerals, vitamins, and fatty acids present in milk. Recent studies have shown that consumption of dairy products appears to be beneficial in muscle building, lowering blood pressure and low-density lipoprotein cholesterol, and preventing tooth decay, diabetes, cancer, and obesity. Additional benefits might be provided by organic milk and by probiotic microorganisms using milk products as a vehicle. New research on dairy products and nutrition will improve our understanding of the connections between these products, the bioactive compounds in them, and their effects on the human body.