CH 4: AAs and Proteins Flashcards

Question

Denatured

Answer 1

Improperly folded, non-functional proteins Disrupt protein shape WO breaking peptide bonds Can occur dt: 1. Urea (H-bonds) 2. pH extremes 3. Temperature extremes 4. Salt concentration (tonicity)

Answer 2

AA order in polypeptide chain Bond: peptide

Answer 3

Initial folding of polypeptide chain a-helix and B-pleated sheet Bonds: H-bonds,

Answer 4

parallel and antiparallel

Answer 5

Interactions bw AA residues located more distantly in the polypeptide chain Bonds/interactions: hydrophobic/hydrophilic interactions 1. (N-C) van der Waals forces bw NP side chains 2. (N-C)H-bonds bw polar side chains 3. (Cov) Disulfide bonds bw cysteine residues 4. (N-C) Electrostatic interactions bw acidic and basic side chains

Answer 6

HydroPHOBIC R-groups fold into interior of protein while hydroPHILIC R-groups are exposed to water on surface of protein

Answer 7

Interaction bw polypeptide subunits Bonds/interactions: same as tertiary NO peptide bond involvement

Answer 8

A favorable rxn used to drive an unfavorable one Possible dt additive free energy changes

Answer 9

HYDROlyses (AKA breaks) chemical bonds includes ATPases, proteases, etc

Answer 10

rearranges bonds win a molecule to form an ISOMER

Answer 11

forms a chemical bond EX: DNA ligase

Answer 12

BREAKS chemical bonds NOT BY oxidation or hydrolysis EX: pyruvate decarboxylase

Answer 13

transfers P group to a molecule from a HIGH energy carrier like ATP EX: phosphofructokinase (PFK)

Answer 14

runs redox rxns EX: oxidases, reductases, dehydrogenases, etc

Answer 15

polymerization: addition of nucleotides to the leading strand of DNA by DNA polymerase III

Answer 16

removes P group from a molecule

Answer 17

transfers P group to a molecule from inorganic phosphate EX: glycogen phosphorylase

Answer 18

hydrolyzes peptide bonds EX: trypsin, chymotrypsin, pepsin

Answer 19

region in an enzyme that's directly involved in catalysis

Answer 20

region in an enzyme that's directly involved in catalysis

Answer 21

reactants in an enzyme catalyzed rxn

Answer 22

AKA "lock and key hypothesis" States: substrate and active site are perfectly complementary

Answer 23

Substrate and active site differ SLIGHTLY in structure Binding of the substrate induce conformational change in enzyme

Answer 24

Protein cleaving Active site has serine residue OH group is NUC and attacks carbonyl C of an AA residue in polypeptide chain

Answer 25

Usually found in proteases Pocket in structure that attracts certain residues on substrate polypeptides

Answer 26

Metal ions or small molecules (not proteins) Required for activity in many enzymes

Answer 27

Organic molecule cofactor Bind to substrate during the catalyzed reaction

Answer 28

Proteins can have diff groups covalently attached to them Regulates activity, lifespan, and location EX: P from ATP by protein kinase to hydroxyl of serine, threonine, or tyrosine Phosphorylation either in/activates enzyme Protein phosphorylases use INorganic phosphate INSTEAD of ATP Protein phosphatases reverse phosphorylation

Answer 29

many enzymes/proteins synthesized in inactive forms (AKA zymogens) Activated by cleavage by a protease

Answer 30

When proteins show continuous rapid catalysis if their regulatory subunit is removed

Answer 31

Modification of active-site activity thru interactions of molecules w other specific sites on the enzyme Noncovalent and reversible Can increase or decrease catalysis

Answer 32

End product shuts off enzyme eaerlier in pathway

Answer 33

Stimulation of enzyme by substrate or molecule used in synthesis of the substrate

Answer 34

Rate of formaiton of products from substrates in presence of enzyme

Answer 35

amt of product formed per unit time mol/s depends on substrate concentration [S] and enzyme

Answer 36

when theres so much substrate that every active site is continuously occupied and adding more substrate doesn't increase the reaction rate

Answer 37

substrate concentration where reaction velocity is half its max Formula: Vmax/2

Answer 38

binding of substrate to one subunit increases the affinity of the other subunits for substrate

Answer 39

binding of substrate to one subunit reduces the affinity of other subunits for substrate

Answer 40

molecules compete w substrate for binding st active site inhibition can be overcome by adding more substrate then can outcompete the inhibitor (Vmx NOT affected) can get to the same Vmax but takes more substrate (INCR Km) | Vmax NO change; Km INCR

Answer 41

Bind at allosteric site NOT active site Amt of substrate added DOES NOT displace inhibitor from site (DECR Vmax) Also affects Vmax/2 DOES NOT affect Km since substrate can still bind to active site BUT inhibitor prevents catalytic activity of the enzyme | Vmax DECR; Km NO change

Answer 42

Inhibitor only able to bind to the enzyme-subtrate complex Bind to allosteric sites (like noncompetitive inh) DECR Vmax (limit amt of E-S complex converted to product) and DECR Km | Vmax DECR; Km DECR

Answer 43

Inhibitor can bind to EITHER unoccupied enzyme of E-S complex Km INCR if enzyme has GREATER affinity for the inhibitor in free form Km DECR if E-S complex has greater affinity for inhibitor if there's EQUAL affinity in both forms--> actually noncompetitive | Vmax DECR; Km varies

CH 4: AAs and Proteins Flashcards

(70 cards)