quiz 1.3 enzymes to metab Flashcards
conponents of holoenzyme
apoenzyme
cofactor
name ng compelte na enzyme
holoenzyme
organic cofactors can be ____ ______
prosthetic
2nd subtrate
inorganic cofactors may be ____ ____
metallo enzyme
ion activators
are cofactors heat stable or labile?
stable
mechanism of action of cofactors
transfer and/or accept functional groups
at the end of the rxn, coenzymes _______
revert to orig state
coenzymes mostly derived from
vitamins
NAD is derived from
nicotinic acid
LIPOIC ACID is derived from
none
pyridoxal phosphate is derived from
pyridoxine vit b5
biochtin is derived from
biotin
coenzymes not derived from vits
cenzyme q
tetrahydrobioprotein
lipoic acid
classif of coenzymes
thos that tranfer H
those that transfer pther than H
where is the active site of NAD
C4 or pyridine ring
rxns involving NAD conezyme
LDH
malaye dehydrogenase
rxns using NADP
G6PD reductive biosynthesis (NADPH)
conezyme to succinic acid dehydrogenase is tightly bound thru
histidine
end product: fumaric acid
rxns using FAD
succinic acid dehydr
fatty acylCoA
l-amino acid oxidase (FMN)
absorbance for FAD/FADH2 and ano itsura
450nm
FAD intense color
FADH2 colorless
the ubiquitous coenzyme
ubiquinone
structure of uniquinone
has benzoquinone with side chains of repeating isoprenoid unis
active sites of uniquinone
C1 and 4
rxn where may ubiquinone
etc
absorbance ng ubiquinone and ano itsura
270-290nm
oxidized form absorbs but disappears when reduced to hudroquinone form
conezyme fo the aromatic amino acids
tetrahydrobiopterin
thiamine pyrophosphate is derived from
thiamine B1
structure ng TPP
subsituted pyrimidine linked to thiazole ring with terminal phosphate
TTP requires
Mg++
TPP is ainactivated by
thiaminase found in raw fish
rxns using TPP
puruvic decarboxylase (nonoxid) pyruvic dehydrogenase (oxid) transkeolase
active site ng TPP
C2 ng thiazole ring
rxns using tetrahydrobiopterin
phenylalanine hydroxylase
tryptophan hydroxylase
action of TPP
transfers binds aldehyde and ketol groups thru its carbanion center
2 forms of lipoic acid
cyclic/oxidized
open:reduced
action of lipoic acid
sulfur group accepts and transfers acyl groups and H+
coenzyme A is derived from
pantothenic acid
active site g coenzyme A
ung sulfur sa dulo kung saan man un
structure ng bicytin
imidazolone ring fused with tetrahydrothiophene linked with valeric acid
biocytin is inactivated by
avidin in raw egg white
biocytin is derived from
nbiotin
mechanism or action ng biotin
carboxylation
ano ung mga may lysine na coenzyme
biocytin
lipoic acid
rxns using biocytin
acetyl CoA carboxylase
pyruvate carbyxolase
propionyl carboxylase
methylmalonyl CoA carboxylase
2forms of pyridoxal phosphate
pyridoxal phosphate
pyridoxamine phosphate
active site ng pyridoxal phosphate
aldehyde group at C4
pyridoxal phosphate reacts with alpha amino of amino acid substrate to form
schiff’s base
three rxns that lyridoxal phosphate uses
transamination
decarboxation
racemization
pyridoxal phosphate is k inhibited by
isoniazid (INH) antiTb drug
pyridoxal phosphate binds to what of enzyme
lysine
how is schiff’s base formed
pyridoxal bla reacts with alpha amino of amino acid substrate
rxns using pyridoxal bla
ALT AST
amino acid decarbo
amino acid racemase
transaminase mechanism
pyrudoxal bla > aldimine > ketimine > puridoxamine
me hanism where intermediate products are released even before all substrate added
ping pong
structure ng tetrahydro flouc acid
pterin rin linked to p-aminobenzoic acid bound to glutamic
avtive sites ng terragydrofolic nla
N5 ng pterin ring
N10 ng PABA
conezyme inhibited by
folate antagonists
like methotrexate and sulfonamides
rxns using tetrahydrofolate
serine hydroxymethyl transferase
thumidile synthetase
formyl synthetase
rxns that cobamide coenz use
racmization:isomerization
transmethylation
2forms ng cobamide coenz
deoxyadenosyl conalamin
methylcobalamin
rxns using cobamide coenz
methylmalonyl CoA mutase
methionine synthase
active sites of FAD/FMN
N1 and 5
special com[onent of FAD/FMN
isoalloxazine ring
the coenzyme used in ETC
ubiquinone
a rxn using coenzyme A that activates palmitic acid for use
fatty acyl CoASH synthase
class 1 enzyme
oxidoreductases
class 2 enzyme
transferases
class 3 enzymes
hydrolases
class 4 enzymes
lyases
class 5 enzymes
isomerases
class 6 enzymes
ligases
refers to the protein part of the enzyme
apoenzyme
refers to the nonprotein part of the enzyme
cofactor/prosthetic group
the complete active enzyme is called
holoenzyme
in transferases, generally, the addition of _____ stimulates activity of receptor
phosphate
this is the regulation of attachment of whatever bla di ko na-note
covalent modification
what is the action of hydrolases
addition of water to break bonds
enzymes that are present at a constant amount in the cell
constitutive/housekeeping
enzymes that is induced by a particular substrate (genetic control)
inducible
model that states the binding site contains amino acid residues rearranged in complementary 3D surface which bind the substrate through various interactions
rigid tempate model (lokc and key)
who formulated lock and key model of active sites
fischer
who formulated the induced fit model of active sites
koshland
model that states that as the substrate binds, te enzyme undergoes a conformational change which positions the side chains of the amino acids in the active site and increases the number of boinding interactions
induced fit model
two perspectives that explain the action of enzymes
thermodynamic changes
processes at the active site
difference in free energy between transition and substrate is called
Gibbs free energy of activation
diff. processes at the active site
proximity/orientation effect desolvation effect acid base catalysis covalent catalysis strain effect metal coordination effect
the reacting groups are close enough or properly oriented as to favor formation of products
orientation/proximity effects
removal of water molecules accelerate enzymatic rxns
desolvation effects
removal of _______ accelerates enzymatic rxns
water
amino acid side chains on the enzyme acts as both proton acceptor and donor
acid base catalysis
covalent catalysis is aka
nucleophilic catalysis
nucelophilic side chains of amino acids on enzyme attacks nucleophilic parts of substrate and form covalent bonds
covalent catalysis/nucleophilic catalysis
conformational change subsequent to substerate binding may lead to distortion on some parts of the substrate
bond distortion/strain effects
etal ions acts as lewis acids which can accept electron pair to form a sigma bond
metal coordination effects
metalloenzymes are ______ bound
tightly
metal-activated enzymes are _____ bound
loosely
________________ always present cofactor metal ion
magnesium
the plot of pH vs. enzyme activity and temp vs activity gives a _____ shape
bell
ps. optimum pH and temp at peak
the enzymes are ______ beyond optimal pH and high temps
denatured
enzyme activity _______ proportionately to the conc. of th enzyme
increases
substrate concentration is shown in what graph
Michaelis Menten saturation graph
as subs. conc. increases, velocity increase only to a point when _________
enzyme is saturated with the substrate
a _____________ is obtained when activity of enzyme is plotted against substrate conc.
rectangular hyperbola
vmax _____ and km ______ with competitive inhibitors
normal; inc
vmax _____ and km ______ with noncompetitive inhibitors
dec; same
vmax _____ and km _____ with uncompetitive inhibitors
dec; dec
amount of activity that catalyzes the transformation of 1 umol of substrate per minute under specified conditions
IU
number of enzyme units per milligram of protein
specific activity
units of enzyme activity per umol pf enzyme
turnover rate or catalytic constant (kcat)
amount of enzyme activity that transform 1 mole of substrate per second
katal(kat)
specific rate constants of the reversible rxn
ks
ther eciprocal of the michaelis menten
lineweaver burke
slope in the lineweaver burke
km/vmax
is defined as the substrate concentration at 1/2 the maximum velocity
km
allosteric enzymes give _____ curves of V vs S
sigmoidal shaped
the concerted kung anuman to is aka
Monod-Wyman-Chageux
the sequential kung anuman to is aka
koshland-Nemethy-Filmer
model that describes allosteric transitions of proteins made up of identical subunits
Monod-Wyman-Chageux
This model of allosteric regulation holds that subunits are not connected in such a way that a conformational change in one induces a similar change in the others.
koshland-Nemethy-Filmer
binding of one ligand to one protomer can affect the binding of the same ligand to another protomer
homotropic interactiond
binding of one ligand affects the binding of a different ligand to another protomer
heterotropic interactions
means of enzyme regulation
allosteric effectors
reversible covalent modif.
stimulation and inhibition of control protein
proteolytic activation
inactive precursors of enzymes are called
zymogen/ptoenzymes
intracellular signaling that involves two mechanism
juxtacrine signaling
the two emchanism in juxtacrine signaling
gap juntion channels
interaction of proteins expressed on the serface of sender cell
signal transduction that involves hormones secreted and long distance transport to target cells
endocrine signaling
transduction taht involves molecules secreted into its immediate or local environment
paracrine
a signaling specific to neurons
synaptic or neuronal signaling
