Reaction Kinetics and Inhibition of Adenosine Kinase from Leishmania Donovani
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
Reaction Kinetics and Inhibition of Adenosine Kinase from Leishmania Donovani
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| Creator |
Bhaumik, Dipa
Datta, Alok K. |
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| Subject |
Structural Biology & Bioinformatics
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| Description |
The reaction kinetics and the inhibitor specificity of adenosine kinase (ATP:adenosine 5'-phosphotransferase, EC 2.7.1.20) from
Leishmania donovani, have been analysed using homogeneous preparation of the enzyme. The reaction proceeds with equimolar
stoichiometry of each reactant. Double reciprocal plots of initial velocity studies in the absence of products yielded intersecting
lines for both adenosine and Mg2--ATP. AMP is a competitive inhibitor of the enzyme with respect to adenosine and noncompetitive
inhibitor with respect to ATP. In contrast, ADP was a noncompetitive inhibitor with respect to both adenosine and ATP,
with inhibition by ADP becoming uncompetitive at very high concentration of ATP. Parallel equilibrium dialysis experiments against
[3H]adenosine and [~/-32p]ATP resulted in binding of adenosine to free enzyme. Tubercidin (7-deazaadenosine) and 6-methylmercaptopurine
riboside acted as substrates for the enzyme and were found to inhibit adenosine phosphorylation competitively in
vitro. 'Substrate efficiency (Vm,x/K~)' and 'turnover numbers (Kc,t)' of the enzyme with respect to specific analogs were determined.
Taken together the results suggest that (a) the kinetic mechanism of adenosine kinase is sequential Bi-Bi, (b) AMP and
ADP may regulate enzyme activity in vivo and (c) tubercidin and 6-methylmercaptopurine riboside are monophosphorylated by
the parasite enzyme
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| Publisher |
Elsevier
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| Date |
1988
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/1457/1/MOLECULAR_AND_BIOCHEMICAL_PARASITOLOGY__Volume_28___Issue_3___Pages_181%2D187_%2C1988[45].pdf
Bhaumik, Dipa and Datta, Alok K. (1988) Reaction Kinetics and Inhibition of Adenosine Kinase from Leishmania Donovani. Molecular and Biochemical Parasitology, 28 (3). pp. 181-187. |
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| Relation |
http://dx.doi.org/10.1016/0166-6851(88)90002-3
http://www.eprints.iicb.res.in/1457/ |
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