5 Flashcards
what are bound molecules called
ligands
is ligand binding covalent
nah
where does ligang binding occur and what interactions help it
H-bonds, ionic interactions, hydrophobic ,van der waals
is ligand binding cooperative or non-cooperative
both
what are cofactors
additional chemical components that assist in enzyme function
what are the two types of cofactors
metal ions and coenzymes
what is a prosthetic group
metal ions or coenzymes associated with a protein
name all the enzyme types and classifications
- oxidoreductase
- transferase
- hydrolase
- lyases
- isomerase
- ligase
- translocase
what category do kinases fall into?
trasnferases
what are lyases also called
synthases
what category do dehydratases and decarboxylases fall into
lyases
what are ligases also called
synthetases
EC 3.4.21.4 describe what each number means
class substrate mechanism specificity
what are the 4 ways in which enzymes increase the reaction rate
participate in the reaction
desolvation
proximity and orientation
stabilizing transition state
what are the 3 ways in which enzymes can participate in a reaction
acid/base catalysis
nucleophilic catalysis
metal ion catalysis
how does RNase act as an acid/base catalyst
His 12 = base
His 119 = acid
what does pH sensitivity relate to in catalysis
acid/base reactions
nucleophilic reactions
denaturation
how can metal ions participate in a reaction
binding/orientation
stabilize TS
reduction / oxidation centres
what is carbonic anhydrase
metalloenzyme
how does PEP carboxykinase work
assisted by metal ion cofactors
active site brings groups together
phosphoryaltes pyruvate
what enhances the difference between activation energies
transition state not substrate
what is the nucleophilic AA in hexokinase
Asp
what kind of enzymes are serine proteases
hydrolases
how many domains in serine proteases
2
what kind of domains in serine proteases
beta barrels
are serine proteases extracellular or intracellular
disulphide bridges extracellular
how are serine proteases synthesizes
zymogens
how are serine proteases activated
cleavage of peptide chain
what composes the catalytic triad
His 57 (acid/base)
Ser 195 (nucleotide)
Asp 102 (modulation of His 57)
what forms the oxyanion hole
Gly 193 and Ser 195
which amino acids contribute to zymogen activation
Asp 194 and Ile 16
where does chymotrypsin cleave peptides
after large hydrophobic
where does trypsin cleave peptides
after large positively charged residues
where does elastase cleave peptides
SMALL nonpolsr
what is the function of the oxyanion hole
TS stabilization
what area from the AA form the oxyanion hole
backbone NH
