Amino acids and enzymes Flashcards Preview

Round 2 > Amino acids and enzymes > Flashcards

Flashcards in Amino acids and enzymes Deck (20):
1

ionizable groups

protonated under acidic conditions--> low pH, positively charged
deprotonated under basic conditions--> high pH, negatively charged
neutral at physiological pH

2

pKa of ionizable groups

pKa value for carboxylic acid group and for amino group
if pH is less than pKa the species is protonated
if pH is greater than pKa the species is deprotonated

3

titrations of amino acids

titration of each proton as a distinct step
half equivalence point is at pKa value
equivalence point is at the pI
looks like 2 monoprotic titration curves, with both half equivalence points equaling the pKa values

4

isoelectric point of amino acids

the pH at which the molecule is electrically neutral
it is a zwitterion

5

sequencing

lab technique used to determine primary structure of a protein
most easily done using the DNA that coded for that protein, but can be done from protein itself

6

conjugated proteins

derive part of function from covalently attached molecules called prosthetic groups
can be organic molecules, vitamins or metal ions
can be lipids, carbohydrates, and nucleic acids

7

oxidoreductase

enzyme catalyze oxidation-reduction reactions
transfer of electrons b/w biological molecules

8

transferases

enzyme catalyze movement of a functional group from one molecule to another

9

hydrolases

catalyzes the breaking of a compound into 2 molecules using the addition of water

10

lyases

catalyzes the cleavage (breaking) of a compound into 2 molecules
*does not use water as substrate and don't act as oxidoreductases
may also catalyze the synthesis of 2 molecules, often small molecules

11

isomerases

catalyze rearrangement of bonds within a molecule
can catalyze runs b/w stereoisomers and constitutional isomers

12

ligases

catalyze addition or synthesis reactions
generally b/w large similar molecule
often require ATP

13

apoenzyme

enzyme without cofactor

14

holoenzyme

enzyme containing cofactor

15

cooperative enzymes

have multiple subunits and multiple active sites
2 states: high affinity tense (T), or low affinity relaxed (R)
binding of substrate encourages the transition of there submits from T state to R state--> increasing likelihood of substrate binding to other subunits

16

competitive inhibition

inhibitor bind to active site
increases Km
v(max) is unchanged
overcome by adding more substrate

17

noncompetitive inhibition

inhibitor bind to allosteric site, which induces a change in enzyme conformation
Km is unchanged
v(max) is decreased

18

mixed inhibition

inhibitor bind to either the enzyme or the enzyme-substrate complex, different affinity for each
bind at the allosteric site
can increase or decrease Km, depending on where inhibitor binds--> to enzyme=increase, to complex=decrease
v(max) is decreased

19

uncompetitive inhibition

bind to enzyme-substrate complex and lock the substrate to the enzyme, preventing its release
Km is decreased
v(max) is decreased

20

zymogen

enzyme that is secreted in an inactive form and must be activated by cleavage
exp. are digestive enzymes