Choose the correct statement about allopurinol: A. It is a purine antimetabolite with antineoplastic activity B. It is a competitive inhibitor of xanthine oxidase C. It is inactive itself, but its metabolite alloxanthine is a competitive inhibitor of xanthine oxidase D. Both allopurinol as well as its metabolite alloxanthine are noncompetitive inhibitors of xanthine oxidase

1 Answer

Answer :

B. It is a competitive inhibitor of xanthine oxidase

Related questions

Description : All of the following statements about allopurinol are true except (A) It is a structural analogue of uric acid (B) It can prevent uric acid stones in the kidneys (C) It increases the urinary excretion of xanthine and hypoxanthine (D) It is a competitive inhibitor of xanthine oxidase

Last Answer : Answer : A

Description : Physostigmine is a competitive inhibitor of (A) Xanthine oxidase (B) Cholinesterase (C) Carbonic anhydrase (D) Monoamine oxidase

Last Answer : Answer : B

Description : Select the antimetabolite which is toxic to Leishmania but not to mammalian cells: A. Allopurinol B. Cytarabine C. 6-Mercaptopurine D. 6-Thioguanine

Last Answer : A. Allopurino

Description : A drug which prevents uric acid synthesis by inhibiting the enzyme xanthine oxidase is (A) Aspirin (B) Allopurinol (C) Colchicine (D) Probenecid

Last Answer : B

Description : A drug which prevents uric acid synthesis by inhibiting the enzyme xanthine oxidase is (A) Aspirin (B) Allopurinol (C) Colchicine (D) Probenecid

Last Answer : (B) Allopurinol

Description : Allopurinol lowers the plasma concentration of: A. Hypoxanthine B. Xanthine C. Uric acid D. All of the above

Last Answer : C. Uric acid

Description : Mammals other than higher primates do not suffer from gout because they (A) Lack xanthine oxidase (B) Lack adenosine deaminase (C) Lack purine nucleoside phosphorylase (D) Possess uricase

Last Answer : Answer : D

Description : In humans purine are catabolised to uric acid due to lack of the enzyme: (A) Urease (B) Uricase (C) Xanthine oxidase (D) Guanase

Last Answer : Answer : B

Description : Choose the correct statement about lovastatin: A. It markedly lowers plasma triglyceride with little effect on cholesterol level B. It is used as an adjuvant to gemfibrozil for type III ... hypercholesterolemia D. It is a competitive inhibitor of the rate limiting step in cholesterol synthesis

Last Answer : D. It is a competitive inhibitor of the rate limiting step in cholesterol synthesis

Description : The following antineoplastic drug is a mitotic inhibitor and causes metaphase arrest: A. Busulfan B. Vincristine C. Cytarabine D. Procarbazine

Last Answer : B. Vincristine

Description : Choose the correct statement about amantadine: A. It is an antimetabolite used for viral infections B. It prevents penetration of the virus into the host cell C. It is used ... during an influenza A2 epidemic D. Concurrent administration of amantadine prevents antibody response to influenza vaccine

Last Answer : C. It is used to protect high risk subjects during an influenza A2 epidemic

Description : Thioguanine differs from mercaptopurine in that: A. It is not metabolized by xanthine oxidase B. It does not cause hyperuricemia C. Its dose need not be reduced when allopurinol is given concurrently D. Both ‘A’ and ‘C’ are correc

Last Answer : D. Both ‘A’ and ‘C’ are correct

Description : Match the following. (A) Inhibitor of (i) Ricin catalytic activity (B) Possess peptide (ii) Malonate bonds (C) Cell wall material (iii)Chitin in fungi (D) Secondary (iv) Collagen metabolite Choose the correct option from the following: (A) ... iv) (ii) (c) (iii) (iv) (i) (ii) (d) (ii) (iii) (i) (iv)

Last Answer : (A) Inhibitor of (i) Ricin catalytic activity

Description : Contrast and compare competitive inhibitors with noncompetitive inhibitors. Which can be overcome by the addition of more substrate?

Last Answer : Competitive inhibitors reduce the productivity of enzymes by blocking substrates from entering active sites. This inhibition is what can be overcome by the addition of more substrate. Noncompetitive ... active site will become less and less effective at helping convert substrate to product.

Description : The following statement is not true of log dose-response curve: A. It is almost linear except at the ends B. It is a rectangular hyperbola C. It facilitates comparison of different agonists D. It can help in discriminating between competitive and noncompetitive antagonists

Last Answer : B. It is a rectangular hyperbola

Description : Choose the correct statement about nefopam: A. It is a nonopioid analgesic which does not inhibit prostaglandin synthesis B. It is an orally active opioid analgesic C. It is an analgesic with potent antiinflammatory activity D. It is a preferential COX-2 inhibitor

Last Answer : A. It is a nonopioid analgesic which does not inhibit prostaglandin synthesis

Description : Which one of the following statements regarding enzyme inhibition is correct? (a) Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein. (b ... large amount of substrate. (d) Non-competitive inhibitors often bind to the enzyme irreversibly.

Last Answer : (b) Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme

Description : A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a: A. Physiological antagonist B. Competitive antagonist C. Noncompetitive antagonist D. Partial agonist

Last Answer : C. Noncompetitive antagonist

Description : A drug which does not produce any action by itself but decreases the slope of the log dose-response curve and suppresses the maximal response to another drug is a: A. Physiological antagonist B. Competitive antagonist C. Noncompetitive antagonist D. Partial agonist

Last Answer : C. Noncompetitive antagonist

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Last Answer : C. It is used orally to treat genital herpes simplex

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Last Answer : D. Both 'B' and 'C' are correct

Description : A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response: Drug ‘R’ is a: A. Partial agonist B. Inverse agonist C. Competitive antagonist D. Noncompetitive antagonist

Last Answer : C. Competitive antagonist

Description : A drug ‘R’ producing no response by itself causes the log dose-response curve of another drug ‘S’ to shift to the right in a parallel manner without decreasing the maximal response: Drug ‘R’ is a: A. Partial agonist B. Inverse agonist C. Competitive antagonist D. Noncompetitive antagonist

Last Answer : C. Competitive antagonist

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Last Answer : C. They are most useful in mild to moderate cases with systolic dysfunction due to dilated cardiomyopathy

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Last Answer : D. Combined therapy with prednisolone and NSAIDs carries higher risk of gastric bleeding

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Description : Which of the following categories of medications may result in seizure activity if withdrawn suddenly? a) Tranquilizers Abrupt withdrawal of tranquilizers may result in anxiety, tension, ... may cause excessive respiratory depression during anesthesia due to an associated electrolyte imbalance.

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Description : Choose the correct statement about latanoprost: A. It is a PGF2α derivative used in glaucoma B. It is a selective α1 blocker used in benign hypertrophy of prostate C. It is a 5-α- ... reduce the size of enlarged prostate gland D. It is a PGE2 analogue used intravaginally for cervical priming

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Description : Choose the correct statement about latanoprost: A. It is a PGF2α derivative used in glaucoma B. It is a selective α1 blocker used in benign hypertrophy of prostate C. It is a 5-α- ... reduce the size of enlarged prostate gland D. It is a PGE2 analogue used intravaginally for cervical priming

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Description : The following is not true of morphine: A. Its 2-glucuronide metabolite is an active analgesic B. Its active metabolite penetrates blood-brain barrier better than morphine C. Its oral: parenteral activity ratio is 1:4 D. It undergoes enterohepatic cycling

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Last Answer : Answer : D

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Description : The high virus selectivity of acyclovir is due to: A. Its preferential uptake by virus infected cells B. Need of virus specific enzyme for its conversion to the active metabolite C. Its action on ... reverse transcriptase which does not occur in noninfected cells D. Both A' and B' are correct

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Last Answer : D. 5-Fluorouracil

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Last Answer : C. Cardiomyopathy

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Last Answer : D. Both ‘B‘ and ‘C

Description : What does the noncompetitive inhibitor bind to?

Last Answer : In the uncompetitive inhibition, the inhibitor binds directly tothe enzyme-substrate complex but not to the free enzyme. This willaffect the catalytic function of the enzyme but not its substratebinding

Description : A drug which prevents uric acid synthesis by inhibiting the enzyme Xanthine oxidase is (A) Aspirin (B) Allopurinal (C) Colchicine (D) Phenyl benzoate

Last Answer : Answer : B

Description : Hypouricaemia can occur in (A) Xanthine oxidase deficiency (B) Psoriasis (C) Leukaemia (D) None of these

Last Answer : Answer : A

Description : Enzymic deficiency in β-aminoisobutyric aciduria is (A) Adenosine deaminase (B) Xanthine oxidase (C) Orotidylate decarboxylase (D) Transaminase

Last Answer : Answer : D

Description : An autosomal recessive disorder, xanthinuria is due to deficiency of the enzymes: (A) Adenosine deaminase (B) Xanthine oxidase (C) HGPRTase (D) Transaminase

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Description : Lesch-Nyhan syndrome, the sex linked recessive disorder is due to the lack of the enzyme: (A) Hypoxanthine-guanine phosphoribosyl transferse (B) Xanthine oxidase (C) Adenine phosphoribosyl transferase (D) Adenosine deaminase

Last Answer : Answer : A

Description : Molybdenum is a cofactor for (A) Xanthine oxidase (B) Aldehyde oxidase (C) Sulphite oxidase (D) All of these

Last Answer : Answer : D