Raw eggs contain protein Avidin - tightly binds to Biotin (vit B7) and is excreted along with biotin. Biotin is required for all carboxylases. All carboxylases require ATP also. So, enzyme affected is carboxylase which requires Biotin as coenzyme Pyruvate Carboxylase is the first enzyme of gluconeogenesis. Regarding other options: Glycogen Phosphorylase ROLE of Glycogenolysis Requires vitamin B6 (Pyridoxal phosphate0 No relation with glycogen phosphorylase and egg avidin Glucose 6 phosphatase A common enzyme in gluconeogenesis and glycogenolysis Deficiency leads to hypoglycemia and that is called Von Gierke's disease (Type 1 glycogen storage disease). - Von Gierke's disease is the most common glycogen storage disease, especially in children.