Biotin

• Biotin is widely distributed in natural foods.  Intestinal bacterial synthesis of biotin is also a major source of  biotin necessary to satisfy its physiological functions.
• Raw egg white contains a heat-labile protein, avidin, which tightly binds biotin and prevents its absorption.
• Biotin functions physiologically as a coenzyme of various carboxylase reaction enzymes (eg., pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase).