Shepherd, Mark and Hunter, C.N. (2004) Transient kinetics of the reaction catalysed by magnesium protoporphyrin IX methyltransferase. The Biochemical journal, 382 (Pt 3). pp. 1009-13. ISSN 1470-8728.
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Magnesium protoporphyrin IX methyltransferase (ChlM), an enzyme in the chlorophyll biosynthetic pathway, catalyses the transfer of a methyl group to magnesium protoporphyrin IX (MgP) to form magnesium protoporphyrin IX monomethyl ester (MgPME). S-Adenosyl-L-methionine is the other substrate, from which a methyl group is transferred to the propionate group on ring C of the porphyrin macrocycle. Stopped-flow techniques were used to characterize the binding of porphyrin substrate to ChlM from Synechocystis PCC6803 by monitoring tryptophan fluorescence quenching on a millisecond timescale. We concluded that a rapid binding step is preceded by a slower isomerization of the enzyme. Quenched-flow techniques have been employed to characterize subsequent partial reactions in the catalytic mechanism. A lag phase has been identified that has been attributed to the formation of an intermediate. Our results provide a greater understanding of this catalytic process which controls the relative concentrations of MgP and MgPME, both of which are implicated in signalling between the plastid and nucleus in plants.
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||Mark Shepherd|
|Date Deposited:||01 Sep 2011 16:11|
|Last Modified:||27 Jun 2012 09:21|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/28094 (The current URI for this page, for reference purposes)|
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