Day 9 Flashcards
two categories of protein functions
catalytic and noncatalytic
are most enzymes proteins or RNA molecuels
most are proteins, some are RNA molecules
1+ inorganic ions, such as Fe, Mg, Mn, or Zn
cofactor
complex organic or metalloorganic molecule that act as transient carriers of specific functional groups
coenzymes
how are most coenzymes derived
from vitamins
coenzyme or cofactor that is tightly bound
prosthetic group
an enzyme with its bound coenzyme/cofactor
holoenzyme
the protein only portion of a holoenzyme
apoenzyme or apoprotein
enzyme class that transfers electrons
oxidoreductases
enzyme class that does group transfer
transferase
hydrolysis, what enzyme class
hydrolases
cleaveage of C-C, C-O, C-N or other bonds by elimination, leaving double bonds or rings or addition of groups to double bonds
lyases
transfer of groups within molecules to yield isomeric forms
isomerases
formation of C-C, C-S, C_O, and C-N bonds by condensation reactions coupled to cleavage of ATP or similar cofactor
ligases
movement of molecules or ions across membranes or their separation within membranes
translocases
add phosphate groups to substrates or other enzymes
kinases
provides a specific environment in which a given reaction can occur more rapidly
active site
the molecule that is bound to the active site and acted upon by the enzyme
substrate
starting point for either the forward or reverse reaction
ground state
the point at which decay to substrate or product are equally likely
transition state
how is activation energy lowered (3 ways)
binding energy, covalent bonding, enzyme function is impacted by binding specificity
difference between the ground state energy level and the transition state energy level
activation energy
how is binding energy used in lowering AE
energy taken from non covalent interactions between enzyme and substrate or receptor and ligand
causes changes in the substrate and provides a lower energy, alternative pathway
covalent bonding
two models of binding specifity
induced fit, lock and key
types of catalysis
acid basis catalysis, covalent catalysis, metal ion catalysis
protons transferred between E and S or intermediate
acid base catalysis
uses H+ and OH- ions in water
acid base catalysis
transient covalent bond forms between E and S
covalent catalysis
help with orientation, stabilize charge, mediate red-ox rxns, can be bound to E or free
metal ion catalysis
determining the rate of a rxn and how it changes in response to changes in experimental parameters
enzyme kinetics
initial transient pd during which ES builds up; VERY brief, often too short to be observed
pre steady state
period during which [ES] and other intermediates remain constant
steady state
the traditional analysis of reaction rates
steady state kinetics
what remains constant in our assumptions
ES and S concentrations
what is greater than what in our assumptions
[S]»_space;» [E]
