active site

Induced Fit

postulated that once substrate was in place, the enzyme changed conformation to bind it better and stabilize the transition state

acid-base catalysis, covalent catalysis, catalysis by approximation, metal ion catalysis

what are the 4 catalytic mechanisms used by enzymes?

acid-base catalysis

A proton is transferred between the enzyme and the substrate

donates

acid catalysis

• enzyme ______ a proton to substrate

takes

Base catalysis

• enzyme _____ a proton from substrate

Covalent Catalysis

A covalent bond forms between the enzyme and the substrate during formation of the transition state.

Catalysis by Approximation

Relevant when a reaction involves more than one substrate.

• Substrates are brought together in favorable orientation

DEKR CHSY

What amino acids can be proton donors/acceptors in acid-base catalysis?

ser, his, asp

what amino acids make up the catalytic triad?

nucleophile

The catalytic triad is very effective in generating a __________

covalent catalysis, acid-base catalysis

What are the catalytic strategies of Chymotrypsin & Lysozyme?

Chymotrypsin uses ______ (reactive nucleophile - Ser) and ______ (proton donors and acceptors - His & Asp)

ser, his, asp

What are the catalytic strategies of Chymotrypsin?

• Chymotrypsin uses covalent catalysis (reactive nucleophile - __) and acid-base catalysis (proton donors and acceptors ___ & ____)

asp, glu

What are the catalytic strategies of Lysozyme?

• Lysozyme uses covalent catalysis ( reactive nucleophile _____) and acid-base catalysis (proton donors and acceptors ______)

Metal Ion Catalysis

Metal ions may:

• facilitate the formation of nucleophile or even serve as an electrophile

• may serve as a bridge between enzyme and substrate, holding the substrate in an appropriate

  conformation for a reaction

induced fit

what is the more accepted model for how substrates bind to enzymes?