Abstract Riboflavin. or vitamin B2. is an essential nutrient that serves as a precursor to flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). The binding of the FAD and/or FMN cofactors to flavoproteins is critical for regulating their assembly and activity. https://www.remtavares.com/best-offer-Merrick-Backcountry-Grain-Free-Kitten-Pate-Canned-Wet-Cat-Food-5-5-oz-Cans-Case-of-24-p14288-limited-choice/