Bio Chemistry

BIOCHEMISTRY 3(2+1)

Lesson 16 : Metabolic Pathways

Methods of metabolic pathway regulation

1. Feedback inhibition
• product of pathway controls its own rate of synthesis
• occurs in the first committed step




• advantage is obvious --> prevention of intermediate accumulation
2. feed forward activation (positive feedback)
• metabolite produced early in pathway activates an enzyme later in pathway
• also prevents accumulation of intermediates




3. allosteric activators and inhibitors – active site/receptor activators ( eg. enzymes )
4. covalent modification
• addition of phosphoryl groups via protein kinases
• removal of phosphoryl groups via phosphatases