Ch 8.1 Lecture

produce enzymes that take a substrate and produce light

immense catalytic power

• - lowers Ea
• - speeds up and makes a reaction easier
• - enzymes do not change

Highly specific

Highly regulated: can produce enzymes in proenzyme form, meaning its sythesized in correct order and almost completely folded. But, one change makes it functional. it is activated when needed

K

carbonic anhydrase

break peptide bond by adding a cofactor, which is water

• They are highly specific for the bond they break 
• ex: One that breaks the bonds that occur after Lys and Arg

convert one form of energy to another

• light--> sugar
• sugar--> ATP
• ATP--> mechanical work
• ATP--> electrical gradients

science concerned with the relationship between heat and work

The total energy of a system (whatever we are trying to study/ anything inside a barrier) and its surroundings is constant

path doesn't matter form A--> B. All that matters are the energies

dE=Esubb-Esuba=Q-W

• Esubb: system when we end the process
• Esuba: system when we start process
• Q: heat absorbed by system
• W: work done by system

we can't determine whether a reaction is spontaneous or nonspontaneous. So, we look at surroundings.

A process can occur spontaneously only if the sum of the entrophies of the system and its surroundings increase

- all entropy increases. 

if disorder increases, then, yes, its spontaneous

It is spontaneous. This is because release of heat increases disorder, making it spontaneous. Even though we created a more ordered system, the entropy of the surroundings increaseed

dStotal=DSsystem+dSsurroundings (we don't always know DSsurroundings)

dSsrroundings= dSsystem-dHsystem/T

dStotal= dSsystem-dHsystem/T

-TdSsystem= dHsystem-TdSsystem

dG=dHsystem-TdSsystem

When 

dSsystem > dHsystem/T

• or 
• TdSsystem> dHsystem

dG=dHsystem-TdSsystem <0

• when dG is negative= spontaneous
• when dG is positive= nonspontaneous
• when dG equals 0= equilibrium

Although folding is more ordered, hydrophobin amino acids get inside to hide from the water and hydrophilic amino acids reposition themselves outside. If the hydrophobic amino acids remain outside, it causes water to become ordered adn form a cage around them. When inside, water is free to act with bulk water and get more disordered

• a relationship between equilibrium constants and free energy change under standard conditions. Given by:
• k'eq=10^(-Go/1.36)
• The 1.36 comes from multiplying the 2.303 by the RT

biochemists created standard conditions (denoted with a ^o  sign) for studying the reactions. 

Then, they added pH of 7, which is denoted by the apostrophe (')

As K'eq increases, dG^o  decreases at standard conditions at pH 7

Regardless of whether an enzyme is added, the reaction will still have the same equilibrium point/ end point. 

• What an enzyme does is speed up the reaction. 
• Therefore, without an enzyme added, it just takes a longer time to reach this equilibrium.

how much free energy is associated with various steps

that is Gibbs Free energy of activation

Highest free energy state that a molecule has to go through to be a product

True

all the weak bonds have energy associated with it. Enzymes help by: 

• - bringing enzymes closer together
• - stressing the substrates to make the TS more attainable

It is the brief period of time that enzymes comes in to react with the substrate

E + S --k1--> ES --k2--> E + P

The ES can continue to convert substrate to product; enzyme not altered

when all are bound together

the reaction velocity goes up but wouldn't reach the max velocity point because not all can react at the exact same time

1) the reaction velocity (how much product formed)

2) taking a look at the active sight only to find that amino acids and prosthetic groups surround the side and have ways of interacting with substrate the best; one ideal substrate that can fit in

3) Spectrophotometer to see how enzymes change when mixed with substrate

4) primary sequence of amino acids (6 out of the 29 form the active site and are required for a reaction to take place); the rest of the AAs form the shape that allows them to fit perfectly in the active site

Once in the active site, covalent bonds can form eventually, but not initially. Hydrogen bonds, ionic bonds, hydrophobic interactions, etc. form. The higher the amount of weak interactions that occurs, the better the chance for substrate

lock and key fit

induced fit

weak interactions hold the substrate and active site together. The substrate fits perfectly into the active site

Only the right substrate will react. The enzyme, prior to binding, has all of the components needed to bind, but it isn't positioned properly. When the substrate comes in, it is fit perfectly in via an induced fit.