Enzyme and Cofactor Classes Flashcards
Oxidoreductases
Aox + Bred Ared + Box
oxidase, hydroxylase: transfer O2 atoms to water or to substrate and water;
O2–> H20
dehydrogenase, peroxidase, reductase;
oxygenase (transfer both O2 atoms to substrate;
cytochrome p450
Common coenzymes of oxidoreductases
NADH, NADPH, FADH2
Transferase
AB+CA+BC
name: which chemical group is transferred or what chemical is synthesized
aminotransferase
transferase; transfers amine group (transaminase)
kinase
transfers a phosphate group
Synthase
indicates what kind of product is formed (glycogen synthase)
Hydrolase
Breaks a CX bond using water
X=O, N, S
protease, esterase, phosphatase, peptidase, urease
Lyase
Cleave C-C, C-O, C-S, and C-N bonds by means other than oxidation or hydrolysis;
decarboxylase, aldolase;
reverse reactions to form bonds: synthases; form C=C bonds by removing H2O from COH-CH
isomerase
no atoms lost or added, only rearranged;
epimerase, racemase, mutase
Ligase
Form C-C, C-S, C-O, C-N bonds and require ATP or another nucleotide;
synthetase (has T because it needs ATP)
6 classes of enzymes
oxidoreductases, hydrolase, lyase, ligase, isomerase, transferase
cofactors
vitamins, metal ions;
deficiency causes a range of diseases and without co-factor, respective chemical reaction cannot occur
ATP, ADP/Pi, AMP/PPi
carry phosphoryl groups
Very high energy bond stores chemical energy and leads to protein phosphorylation
NADH/NAD+
Shuttles electrons for redox of biological fuels, helps produce ATP
NADPH/NADP+
Shuttle electrons for oxidation in biosynthesis reactions
FADH2/FAD
FMNH2/FMN
Shuttle electrons for redox of biological fuels
more powerful than NAD’s: very strong oxidizing agents
Always bound to protein (prosthetic groups)
coenzyme A
carries acyl group O=C-R (R=CH3 and longer)
Biotin
Carries CO2 for carboxylation
Tetrahydrofolate
amino acid metabolism;
carries 1 carbon unit to carbon or sulfur
S-adenosylmethionine
carries methyl group to oxygen or nitrogen
Pyridoxal phosphate
cofactor/coenzyme that reacts with amines (NH2, NH) to catalyze amino acid metabolism, transamination reactions
Thiamine pyrophosphate
co-factor/co-enzyme that reacts with aldehydes/ketones to catalyze decarboxylation at the R group
Protease
part of hydrolase group
Cysteine proteases, aspartic proteases, metalloproteases, serine proteases
cysteine protease
active site requires cysteine residue;
papain, calpain, interleukin-1-b converting enzyme