Coenzyme Reaction type P. Thiamine pyrophosphate 1. Acyl group transfer Q. Tetrahydrofolate 2. Transfer of one carbon group R. Flavin adenine dinucleotide 3. Transfer of methyl group S. 5'-Deoxyadenosyl cobalamin 4. Oxidation-reduction 5. Aldehyde transfer
Coenzyme and Reaction Type Matching
This question requires matching specific coenzymes with their primary roles in biochemical reactions.
- P. Thiamine pyrophosphate (TPP): TPP is famously known for its role in decarboxylation reactions and the transfer of aldehyde groups. It acts as a cofactor for enzymes like pyruvate dehydrogenase and transketolase. The matching reaction type is 5. Aldehyde transfer.
- Q. Tetrahydrofolate (THF): THF is a crucial carrier of one-carbon units (e.g., methyl, formyl, methylene groups) essential for the synthesis of nucleic acid precursors and certain amino acids. The matching reaction type is 2. Transfer of one carbon group.
- R. Flavin adenine dinucleotide (FAD): FAD is a prosthetic group derived from riboflavin that participates in oxidation-reduction reactions, acting as an electron acceptor. It is a key component of many oxidases and dehydrogenases. The matching reaction type is 4. Oxidation-reduction.
- S. 5'-Deoxyadenosyl cobalamin (AdoCbl): This is a form of Vitamin B12. While involved in various rearrangements, a prominent role is in the transfer of methyl groups (e.g., in methionine synthesis, although the active form there is methylcobalamin) and other alkyl groups, as well as isomerase reactions. Given the options, 3. Transfer of methyl group is the most appropriate match, commonly associated with cobalamin chemistry.
Matching Summary
Based on the functional roles of each coenzyme:
- P (Thiamine pyrophosphate) matches with 5 (Aldehyde transfer).
- Q (Tetrahydrofolate) matches with 2 (Transfer of one carbon group).
- R (Flavin adenine dinucleotide) matches with 4 (Oxidation-reduction).
- S (5'-Deoxyadenosyl cobalamin) matches with 3 (Transfer of methyl group).
This corresponds to the pairing P-5; Q-2; R-4; S-3.
Important Questions from Enzyme Classification Catalytic and Regulatory Strategies
- An enzyme catalyzes a reaction by
- The activity of an enzyme is expressed in International Units (IU). However, the S.I. unit for enzyme activity is Katal. One Katal is
- Match the entries inGroup I with the enzymes inGroup II.
Group I Group II P. NAD$^+$ 1. Glutathione peroxidase Q. Selenium 2. Nitrogenase R. Pyridoxal phosphate 3. Lactate dehydrogenase S. Molybdenum 4. Glycogen phosphorylase Determine the correctness or otherwise of the following Assertion (a) and the Reason (r)
Assertion: A very low amount of inhibitor can act as an activator for allosteric enzymes.
Reason: Allosteric enzymes follow Michaelis-Menten kinetics.
- Correctly match the Enzyme with its respective Function.
Enzyme Function P. Gyrase 1. Removes a damaged base by cleaving the bond between sugar and base Q. Deadenylase 2. Provides a swivel allowing one DNA strand to rotate around the other R. Glycosylase 3. Catalyses bond formation between 3'-OH and 5'-phosphate end of nucleotides in duplex DNA S. DNA ligase 4. Is an exoribonuclease that removes the poly(A) tail
