Enzymes: how proteins speed up chemistry

Enzymes are proteins that speed up chemical reactions, often by millions of times, by holding their substrates in exactly the right position. These classic structures show active sites, catalytic triads, induced fit and large domain motions. Many of them, such as lysozyme, chymotrypsin and triosephosphate isomerase, are the standard examples in biochemistry courses.

Open Hen egg-white lysozyme in 3D

26 structures

Hen egg-white lysozyme2LYZ
The first enzyme structure ever solved (David Phillips, 1965).
Triosephosphate isomerase1TIM
A nearly perfect enzyme, and the protein that gave the TIM barrel fold its name.
Yeast triosephosphate isomerase with an intermediate analog7TIM
Alpha-chymotrypsin4CHA
A serine protease with the classic Ser-His-Asp catalytic triad.
Trypsin bound to BPTI inhibitor2PTC
Adenylate kinase, open form4AKE
Adenylate kinase, closed form with inhibitor Ap5A1AKE
Compare with 4AKE to see the lids close over the substrates.
Yeast hexokinase B2YHX
Horse liver alcohol dehydrogenase8ADH
Human carbonic anhydrase II1CA2
One of the fastest enzymes known.
Cytochrome P450cam2CPP
Beef liver catalase7CAT
Bovine copper, zinc superoxide dismutase2SOD
TEM-1 beta-lactamase1BTL
Destroys penicillin-type antibiotics, a major cause of antibiotic resistance.
Alkaline phosphatase1ALK
Ribonuclease A5RSA
Ribonuclease T1 with guanylic acid1RNT
Deoxyribonuclease I (DNase I)3DNI
Glycogen phosphorylase b1GPB
Dogfish lactate dehydrogenase3LDH
Xylose isomerase1XIS
Used in industry to make high-fructose corn syrup.
Thermolysin8TLN
Papain9PAP
Glutamine synthetase2GLS
Nitrogenase complex1N2C
Converts nitrogen gas from the air into ammonia.
Human carbonic anhydrase II (AlphaFold)P00918 (AlphaFold)

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