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19 Cards in this Set
- Front
- Back
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Reverse transcriptase is normally found in a. plants b. mitochondria c. retrovirus d. all of the above |
Retro virus
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Plasmids used in recombinant DNA technology typically a. possess a gene for antibiotic resistance b. replicate independently of the host genome c. are circular double stranded molecules d. all of the above e. a and b |
all of the above |
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Holoenzyme |
enzyme (protein) + cofactor (non-protein)
-No activity in the absence of the cofactor |
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Apoenzyme |
Protein portion of holoenzyme |
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Zymogen (Proenzyme) |
catalytically inactive enzyme complex
- ex: chymotrypsinogen |
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Prosthetic group |
tightly bound cofactor that does not dissociate from enzyme
- ex: Biotin |
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Carbonic anhydrase |
-Catalyzes hydration of carbon dioxide -One of the fastest enzymes known -Can hydrate 10^6 molecules of CO2 per sec -Catalyzed reaction is 10^7 times as fast as uncatalyzed one |
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Proteases |
catalyze hydrolysis of peptide bonds |
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Enzymes are highly specific |
precise interaction of substrate with enzyme -specific in terms of reaction and substrate |
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Proteolytic enzymes |
catalyze a different but related reaction in vitro hydrolysis of an ester bond
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Substrate specificity: -Proteolytic enzymes differ markedly in their substrate specificity |
*Papain -wide substrate specificity -cleaves any peptide bond *Trypsin -Specific -cleaves only on the C terminus of Lysine and Arginine residues *Thrombin -Very specific -vatalyzes hydrololysis of Arg-Gly bonds in a particular sequence only |
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cofactors |
the catalytic activity of many enzymes depend on the presence of small molecules called cofactors -Metals -Coenzymes; -often derived from vitamins -small organic molecules which can also be subdivided into two groups -Tightly bound termed prosthetic groups -Loosely bound like co-substrates
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Six major classes of enzymes |
Oxidoreductases Transferases Hydrolases Lyases Isomerases Ligases |
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Oxidoreductases |
oxidation- reduction reaction
Ex: Lactate dehydrogenase |
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Transerferases |
Group transfer reaction
Ex: Nucleoside monophosphate kinase (NMP kinase)
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Hydrolases |
Hydrolysis reactions (transfer of funtional groups to water)
Ex: Chymotrypsin |
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Lyases |
Addition or removal of groups to form double bonds (reaction)
Ex: Fumerase |
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Isomerases |
Isomerization (intermolecular group transfer)
Ex: Triose phosphate isomerase |
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Ligases |
Ligation of two substrates at the expense of ATP hydrolysis
Ex: Aminoacyl-tRNA synthetase |
