Module 3: Chemical Reactions

• transfer of protons from one species to another • most common • change in charge (either charges to neutral or neutral to charged)

switching one group for another *usually see swinging arrow into and out of reaction Types: Nucleophilic, aromatic, acyl

addition of a nucleophile to an electrophile

sub of a Hydrogen on an aromatic ring with another group (NOT Oxygen or nitrogen <- then it would be considered REDOX)

addition of a nucleophile to a carbonyl group (esters, amides, carboxylic acids) or sulfonate group or phosphate group.

• electron rich (provide e- to create new bonds) • Nucleus loving <3 • anions (look for neg charge), heteroatoms w/ lone pair, alkenes, alkynes

• electron poor species • electron loving <3 (carbocations, carbonyl group, alkenes, alkynes) *Hydrogen can never be the electrophile.

• help increase the rate at which the reaction occurs All biochem reactions utilize enzymes and cofactors as catalysts

• increase reaction rate • takes alternate pathway • Catalysts do NOT appear in product • Catalysts are NOT consumed (recycled for something else) - if they were, we would burn too much energy. notice 4 distinct steps (humps) Krebs cycle - glycolysis

• removing a group completely from the molecule look for a double or triple bonds created!!! *usually an arrow going away from reaction

• adding a group to a molecule (usually start with a ketone or aldehyde) *usually arrow coming into reaction

changing the oxidation state of a group on a molecule 1. Oxidation - increase bonds to O or N, or decrease in bonds to H 2. Reduction - decrease in bonds to O or N, or increase in bonds to H *usually see a half circle arrow swinging through reaction (NAD+ to NADH, etc)

• rearrangement of groups within the same molecule • Least common

• globular proteins end in -ase. • main catalysts used in reactions *helps decrease activation energy required for a chemical reaction - makes Delta G negative (Exothermic)

• Efficiency (natural better than chemical/lab catalysts) • Specificity • Regulation

• Gibbs Free energy - want to be negative • a measure of whether or not a chemical process will or will not work. • based on Delta H (enthalpy) and Delta S (entropy) and temperature

Enthalpy - measure of energy difference btwn products and reactants (endothermic & exothermic) We want exothermic - we want to produce energy *we do not want a system that requires energy.

entropy = degree of disorder enzymes create more disorder via confirmational change - we want this!

• Non-protein component required to allow an enzyme to perform its role! - bind with enzyme *REDOX need a co-factor.

Mg, Zn, Cu, Fe, Mn, Ni, Mb (minerals)

vitamin derivitives (usually B vitamins)

• Transferase (sub) • Hydrolase (sub - using water) • Oxidoreductase (redox) • Lyase (elimination) • Ligase (addition) • Isomerases (isomerization)

• Transfer functional groups • Substitution reactions (*acyl, nuclephilic, aromatic) *acyl usually uses hydrolase (look for use of H2O)

• breaks bonds using water!!! • usually substitution reactions (mostly acyl - ester to a carboxylic acid) *saponification (hydrolysis of fats)