Metabolic Pathways

Enzyme Inhibition Types

1) Competitive Inhibition

2) Non-competitive inhibition

3) Uncompetitive inhibition

4) Suicide Inhibition

Competitive Inhibition

• inhibitors of structurally similar to the substrate => enzyme could have a greater affinity for the inhibitor than for the substrate

• e.g. occurs with synthetic drugs

• generally reversible but can be irreversible in some conditions

Define Anatabuse

• A medication for people with alcohol abuse

• Competes with a co-factor named NAD on the binding site for ALDH. Anatabuse is similarly structurally to the NAD

• Exacerbates the hangover symptoms

• Normal metabolism for ethanol:

• ethanol=> oxidation=> acetaldehyde (super toxic)=> breaks down using aldehyde dehydrogenase (ALDH)=> acetic acid (vinegar)

Non-competitive Inhibition

• inhibitor does not to the active site=> binds to the allosteric site (typically the “other site”)

• no products formed

• if inhibitor is released, the product can be formed

• generally reversible but can be irreversible in some conditions

Define the R-A-A System

• hormone system that regulates blood pressure, fluid, and electrolyte balance & systemic vascular resistance

Describe the process of the R-A-A System

• Liver: produces Angiotensinogen (zymogen) continuously

• Kidney: If BP drops (bc low fluid vol)=> baroreceptors outside of the Bowman’s capsule (DCT)=> granular & juxtagomenular cells from BC produce and release renin

• Renin=> converts Angiotensinogen to angiotensin I (slight vasoconstrictor but no much)=> goes to the lungs & comes into contact with ACE=> converts Ang I into Ang 2 (generalized vasoconstrictor)=> constricts vessels and inc blood vessels

• Adrenal: Ang 2=> acts on adrenal cortex=> causing adrenal glands to release Aldosterone (steroid hormone)=> acts on collecting duct or nephron=> dump Na+ back into the body=> water is going to follow=> inc bp (water retention)

Uncompetitive Inhibition

• only binds to the ES complex => allosteric site is created bc of binding of substrate

• doesn’t stop the product being made just slows the process

• generally reversible but can be irreversible in some conditions

Suicide Inhibition

• inhibitor forms COVALENT bonds

• irreversible