ENZYMES Flashcards
(30 cards)
enzymes that remove the elements of hydrogen, H2 or H− plus H+
Dehydrogenases
enzymes that hydrolyze proteins
Proteases
enzymes that catalyze rearrangements in configuration
Isomerases
enzymes that catayze oxidations and reductions
Oxidoreductases
enzymes that catayze transfer of moieties such as glycosyl, methyl, or phosphoryl groups
Transferases
Enzymes that catalyze hydrolytic cleavage of C—C, C—O, C—N, and other covalent bonds
Hydrolases
Enzymes that catalyze cleavage of C—C, C—O, C—N, and other covalent bonds by atom elimination, generating Double bonds
Lyases
enzymes that catalyze geometric or structural changes within a molecule
Isomerases
Enzymes that catalyze the joining together (ligation)of two molecules in reactions coupled to the hydrolysis of ATP
Ligases
are tighty an staby incorporate into a
protein’s structure by covaent bons or noncovaent forces.
Prosthetic Groups
serve functions simiar to those of prosthetic groups an overap with them. They bind weakly an transiently to their cognate enzymes or substrates, forming dissociabe compexes.
Cofactors
serve as recycabe shuttes that transport many substrates from one point within the cell to another.
Coenzymes
refers to reactions for which the ony participating acids or bases are protons or hydroxide ions
Specific Acid-Base Catalysis
Reactions whose rates are responsive to all the acis or bases present
general acid catalysis/ general base catalysis.
In orer to chemicay interact, substrate moecues must come
within bon-forming istance of one another. The higher
their concentration, the more frequenty they wi encounter
one another, an the greater wi be the rate at which reaction
proucts appear. When an enzyme bins substrate moecues
at its active site, it creates a region of high oca substrate concentration, one in which they are oriented in an ideal position
to chemically interact.
CATALYSIS BY PROXIMITY
invove breaking a covaent
bon, enzymes typicay bin their substrates in a conformation that weakens the bon targeted for ceavage through physical
distortion an eectronic poarization
CATALYSIS BY STRAIN
invoves the formation of a covaent bon between the enzyme an one or more substrates. Also provies a new reaction pathway whose activation energy is lower—an rate of reaction therefore faster—than the pathways avaiabe in homogeneous soution.
COVALENT CATALYSIS
model accounted for the exquisite specificity of enzyme–substrate interactions, the impie
rigiity of the enzyme’s active site faie to account for the
dynamic changes that accompany cataytic transformations.
Lock and Key Model by Fischer
which states that as substrates bin to an enzyme, they induce a conformational change that is anaogous to placing a hand (substrate) into a gove (enzyme)
Induced fit Model- Daniel Koshland
Ideal temperature for enzyme work
44- 55 C which is internal body temperature
known as the least amount of energy need for a chemical reaction to take place
Activation energy
what happens when the enzyme is subjected to higher or lower temperatures
Denaturation
what happens when the enzyme is subjected to higher or lower pH values
Ionization
Most enzymes exhibit optimal activity at pH value ______________
5 to 9
