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)
