UWorld Flashcards
phosphate groups are most often added to which functional group?
hydroxyl group (-OH)
where does phosphorylation most typically occur?
on hydroxyl groups (-OH)
which amino acids are most easily phosphorylated?
those with hydroxyl groups
(serine, threonine, tyrosine)
allosteric effectors
bind to proteins at one site and cause a conformational change at another site
SDS PAGE
separates proteins by size (molecular weight)
smaller fragments travel faster / further
proteases
degrade proteins into smaller fragments
by hydrolyzing peptide bonds
what does Kd stand for
dissociation constant
small Kd value = ….
high binding affinity
low tendency for the complex to dissociate
what is the bond that connects amino acids in a protein
peptide bonds
thermodynamic stability of a bond…
refers to its tendency to form or break in chemical reactions
a thermodynamically stable bond…
a bond that forms during a spontaneous reaction
a thermodynamically unsdtable bond forms during a – reaction
forms during a** nonspontaneous** reaction
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non-spontaneous reactions
require energy input in order to proceed4
ATP hydrolysis
the breakdown of ATP to ADP + Pi via the addition of water
thermodynamically stable reaction
spontaneous; proceed without the addition of energy
do not necessarily proceed quickly
what classs of macromolecule are antibodies?
proteins
kinetically stable bonds…
the breakdown of their bonds have slow reaction rates (high activation energy)
antibodies bind via …
noncovalent interactions
precision
when similar results are obtained from trial to trial
whether or not they are accurate
accuracy
accuracy describes how close results reflect and represent a real-world value, assessed by comparison to a “gold standard”
validity
a study is valid if it results are both precise and accurate
what does Kcat represent?
the turnover number: the number of subsrate molecules converted to product pr enzyme per unit of time when the enzyme is saturated with product
enzyme equation: Vmax = …
gibbs free energy vs gibbs standard free energy
equation
true or false: a reaction may be non spontaneous under but spontaneous in vivo
TRUE
what is Gibb’s standard free energy
this is just the free energy of a reaction under standard conditions
le chateliers principle states that…
if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change and reestablish an equilibrium
state function
definition
a property whose value does not depend on the path taken to reach that specific value
example of state functions
temperature, pressure, density, volume, Gibb’s energy free, enthalpy, internal energy, and entropy
path functions
definition and examples
depend on the path taken from one state to another
ex. heat and work
in size exclusion chromatography, larger proteins travel —- than smaller proteins
FASTER
in SDS page, larger proteins travel —- than smaller proteins
slower!!
crude sample
total yield
how much of the desired product is obtained following purification
total yield of a protein can be determined by calculating ——-
total activity (u) of the purified protein
total activity formula
protein purity is represented by —-
specific activity
specific activity
a ratio of the activity of the desired protein to the total mass of protein obtained from purification
specific activity units
activity (u) / total mass (g)
percent yield equation
