Phosphorylases are regulated through multiple mechanisms including allosteric regulation, covalent modification, and gene expression. For instance, glycogen phosphorylase is regulated by allosteric effectors like AMP, which activates the enzyme, and ATP and glucose-6-phosphate, which inhibit it. Additionally, covalent phosphorylation by phosphorylase kinase can convert the less active phosphorylase b to the more active phosphorylase a form.
