exam 2

trypsin

what enzyme cuts chains after arginine and lysine?

cyanogen bromide

what compound cuts peptide chains after met?

true

true or false: an amino acid sequence will fold the same way every time it is produced if the conditions remain the same

primary

the amino acid sequence is the __________ level of protein structure

secondary

the local folding (helix, sheet) of a peptide chain is the ___________ level of protein structure

tertiary

the overall folding of an amino acid is the ___________ level of protein structure

quaternary

the association of different subunits is the __________ level of protein structure

supersecondary structure

groupings of different secondary structures is referred to as the ________________

alpha helix

two negative angles of phi and psi on a Ramachandran diagram

beta sheet

positive and negative angles of phi and psi on a Ramachandran diagram

3.6

alpha helices have how many residues per turn?

true

true or false: max spacing of r groups and hydrogen bonds contribute to the energetically stable forms of both alpha helices and beta sheets

proline

beta hairpin turns have 2-4 amino acids with at least 2 of them being _________

pH, temperature, denaturing chemicals, ionic strength, redox

factors that affect protein stability

decrease

salting in causes a(n) _____________ in stability

increase

salting out causes a(n) ____________ in stability

true

true or false: some proteins require a chaperonin such as GroEl in order to fold correctly

beta sheet, alpha helix

PrP-Sc represents the misfolded form of PrP-c. the misfolded version has more _________ than ____________

adenylate cyclase

activated g protein moves along the membrane to reach an effector molecule, such as ___________

trimeric

g proteins usually have 3 subunits, making them _________ in nature

first messenger

g protein signaling mechanisms are usually initiated by a _______________

humoral immunity

immune response involving antigens binding directly to B cells, causing the production of antibodies

cell mediated immunity

immune response involving the destruction of infected cells by cytotoxic T cells, or the destruction of intracellular pathogens by macrophages

collagen

every third amino acid is gly

alpha keratin

every fourth residue is hydrophobic

fibroin

common sequence is gly-ala or gly-ser, which allows close packing

elastin

rich in glycine, alanine, and valine

ca, troponin

the binding of ____ to ______ results in the movement of tropomyosin and the exposure of the myosin binding site on the actin filament

directly

at low substrate concentration, the rate of reaction would be ___________ proportional to the substrate concentration

competitive inhibitors

affect the value of Km and not Vmax

Km

describes the affinity of an enzyme for a substrate

Km

substrate concentration required to reach 1/2 the max velocity

Km

describes the stability of the ES complex

Km

= (K1 + K2)/k1

lock and key enzyme

active site is specific to the substrate, thereby enhancing forward momentum in the reaction progress

stabilized

the transition state of an enzyme and substrate reaction is ___________ by the specificity of the active site for the substrate

covalent

serine at the active site of serine proteases provides _______ catalysis

acid base

histidine residue in a serine protease provides __________ catalysis

proximity effects

_____________ can be caused by site specificity, can be enhanced by substrate channeling, result in an increased effective concentration of substrate, and function to lower the energy of activation