Active Site of an enzyme, it is a 3 dimensional cleft or crevices

1. • Active Site/s ?

2. Active sites
• The active site of an enzyme is a 3-dimentional
cleft or crevices formed by groups that come
from different parts of the amino acid
sequences.
• It occupies relatively small part of the total
volume of an enzyme.
• Substrates are bound to enzymes by multiple
weak interactions like electrostatic interactions,
hydrogen bonds, van der waals forces,
hydrophobic interactions mediate reversible
interations of biomolecules.

3. *
• The specificity of bonding depends on the
precisely defined arrangement of atoms in an
active site.
• Active sites may include distant residues
• Amino acid residues that are far apart in the
sequence may interact more strongly than
adjacent residues.
• 3 D entity
• Generally complementary! But,
• Conformations do matters! Specificity!

4. • Conformational change :
• Proteins are well known for this property
• “A spatial arrangement of an substituent
groups that are free to assume different
positions in space, where they exists, without
breaking any bonds, due to the freedom of
free bond rotation.”

5. 19.7
Cofactors
and
Coenzymes

7. ENZYME
Pyruvate
dehydrogenase
Mono amine
oxidase
Glycogen
phosphorylase
Lactate
dehydrogenase
Acetyl CoA
carboxylase
Thymidilate
synthase
COENZYMES
Thiamine
pyrophosphate
FAD
Pyridoxal
phosphate
NAD+
Coenzyme A
Tetrahydrofolate
VITAMINS
Thiamine
(B1)
Riboflavin
Pyridoxine
(B6)
Nicotinic
acid- niacin
Pantothenic
acid
Folic acid
REACTION TYPE
Aldehyde transfer
Oxidation – reduction
Group transfer to or
from amino acids
Oxidation – reduction
Acyl group transfer
Transfer of one
carbon component,
thymine synthesis