lecture 2 Flashcards
prion disease
mis-folding of proteins in brain
mad cow
some uses of proteins
enzymatic catalysis transport storage motility structure and support immune protection signaling
four protein structures
primary
secondary
tertiary
quaternary
what is basic building blocks of proteins
amino acids
general formula for amino acids
an alpha carbon attached
- COOH (carboxyl group)(acidic negative charge)
- H2N (amino group- + charge)
- R group (changes per amino acid)
- H
20 amino acids
molecule with both positive and negative charge
zwitterions
are amino acids in L or D formation
L
what is primary protein structure
just the amino acid sequence
what is secondary protein structure
folding/shaping of a local section of polypeptide
a-helix or beta sheet, beta turn. triple helix, coiled coil
what is tertiary protein structure
folding of a complete polypeptide chain
Beta sheet and helix of same polypeptide
what is tertiary structure
how more than one polypeptide interact with one another
beta sheet/helixes of 2 polypeptides
what is the Vmax of an enzyme reaction?
the maximum velocity at which a reaction may occur
what is the Km of an enzyme reaction
the amount of substrate needed in order to reach 1/2 of Vmax
at ph 7, every amino acid has a negative charge on its
carboxyl group (COO)
polypeptide chains are cross linked by S-S bonds due to
cysteine
during chymotrypsin breakdown of a polypeptide, part of the polypeptide is briefly attached covalently to the amino acid
serine
what effect does an enzyme have on the activation energy of the reaction
decreases-
reaction will need less activation energy- reaction is easier to do
a competitive enzyme inhibitor will
not work well when the substrate concentration is high
when an enzyme reaction is inhibited by a noncompetitive inhibitor
the Vmax is lowered and Km is unchanged
sometimes an enzyme reaction is helped by ATP because ATP transiently transfers its ____ to the substrate
phosphate
NADH functions as a coenzyme in biological ____ reactions
catabolic
the enzyme chymotrypsin is secreted from the pancreas as a ____ that needs proteolysis to increase its activity
zymogen (chmyotrypsinogen)
during the cascade of enzyme reactions that occur in the fight or flight syndrome, majority of the enzyme reactions are stimulated by the attachment of ___ to the enzyme
phosphate
what is a polar bond
non-even share of electrons
usually has + and - side
can be uncharged polar
hydrophilic (like water)
(polar bears like water)
non-polar
electrons shared evenly- neutral molecule
hydrophobic (hates water)
basic has what charge
positive charge
acid
negative charge
which amino acid has a SH r group that likes to form disulfide bonds S-S bonds with other animo acids
cysteine
amino acids form __ bonds and are in ___ chain
peptide (covalent)
linear
amino group (NH2)(+) will attach to carboxyl group (COOH)(-)of another animo acid
+ and - parts attach
group of amino acids in a chain
polypeptide
peptide bond
water leaves
C of carboxyl group
binds to N of amino group
catalyzed by enzyme
breaking of bond by adding water
hydrolysis
enzyme to break peptide bonds in proteins
protease
strongest chemical bond when atoms share electrons
covalent
bonds between opposite charges
electrostatic interactions
ionic bonds
salt bridges
polar water molecules can form shells around charged surface residue sidechains, helping to stabilize and solubilize the protein
water shell and charged surface residues
two atoms bearing partial negative charges share a partially positively charged ___ forming a ___ bond
hydrogen
hydrogen
type of bond when animo acids hate water( non polar)
amino acids will fold onto them selves and hide from water
hydrophobic bonds
weak electrical attraction of one atom for another, want to be close but not too close
personal space
Van der Waal Forces
