lecture 5 Flashcards
valine has what side group as a side chain?
isopropyl
leucine has what as a side chain?
isobutyl
isoleucine has what as a side chain?
isobutyl
which amino acid has the largest side chain?
tryptophan
what is responsible for 280nm absorbance?
trytophan
which 2 amino acid has amphiphatic character?
tyrosine, threonine
what properties do trytophan have?
fluorescent
what measure absorbance? and which amino acid has highest?
beers law trytophan
which amino acids are sites of post translational activity?
threonine and serine
which amino acids so 0 glycosylation occur?
threonine and serine
what type of bond does cyteine form with cysteine?
covalent bond
what is most reactive group in proteins?
sulfhydryl
which amino acid has nucleophilic activity?
cysteine
cysteine must be what for effective anaylsis? it also reacts with what?
alkylated. metal ions
what is precursor to antioxidant glutathione?
cysteine
which aa can participate in acid/base reactions?
histidine
which amino acid has guanino group? and what does it do?
arginine, can interrupt protein structure
aa for deamidation reactions (protein ageing)
glutamine
esterification reaction possible in which aa?
glutamate and aspartate
which aa has cyclic imino acid?
proline
amide bond resonance allows for what in the peptide bond?
stability and planar character
which bonds in the peptide bond can rotate?
phi and psi
phi is what?
in between N and alpha carbon
psi is what
in between alpha carbon and carbon
when it comes to forming peptide bond, equilibrium favors what? and kinetics are stable for how many years?
hydrolysis instead of synthesis. 1000
what does phi bond prefer to be?
-120
in alpha helices, how many residues separate h bonding atoms between N and C=O? residues rise at ____A and rotate ____. pitch is ____A
3.6, 1.5, 100 degrees, 5.4
describe feeling of alpha and examples
stiff and rigid. fibrin (blood clots), keratin (hair), cytoskeleton, porcupine quills, tropomyosin (muscle)
ferritin is what type of helice?
alpha
which beta sheet is more stable and why?
antiparallel because of shorter hydrogen bonds between the nitrogen and C=O.
when forming a loop what do you find?
glycine, proline and alanine.
barrels are used usually for what?
nuclear pore complexes, allowing ions to pass through
hairpin turn is what kind of sheer?
beta
are omega loops common?
no
which amino acids are no favored for alpha helices?
valine, isloleucine, threonine. serine, aspartic acid, asparagine
explaine role proline plays in sheets?
disrupts alpha and beta sheets, so it is found in the turns usually in a cis formation
urea does what to proteins?
denatures them by disrupting the water bonds.
explain difference between simple dimer and hetero tetramer
dimer is quaternary structure with dimer of identical subunites. hetero tetramer is composed of different chains
structural plasticity allows for what in hemoglobin?
cooperative oxygen binding
what is a newtonian fluid?
viscosity is constant, even when flowing. when one pushes, viscosity does not change. examples are water, milk, vegetable oils, fruit juices, sugar, and salt solutions
explain non newtonian fluid
viscosity changes when applied force changes. shear thinning- viscosity decreases when force is applied to the fluid. examples- latex paint, molasses, ketchup and saliva
what is the Ph of saliva?
7.4
what allows saliva to act as a lubricative film?
glycoproteins
