Characterization of carrot pectin methylesterase
- Cite this article as:
- Markovič, O., Cederlund, E., Griffiths, W. et al. CMLS, Cell. Mol. Life Sci. (2002) 59: 513. doi:10.1007/s00018-002-8442-6
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The most alkaline form of pectin methylesterase was purified from ripe carrot roots and used for structural analysis. Determination of an N-terminal blocking group and of the primary structure allowed comparisons with other forms, and facilitated crystallographic determination of the three-dimensional structure. The mature enzyme has 319 residues and the N-terminal blocking group was shown to be a pyroglutamyl residue derived from a glutaminyl cyclization. Few other methylesterases have been isolated and assigned to exact mature forms, and together with the present enzyme, only two have been analyzed in three-dimensional structure. However, comparison of 39 forms, mainly from GenBank data, reveals clear relationships and identifies sub-groups of this enzyme type, deviating in structure but centering around two functionally important and conserved Asp residues at positions 136 and 157 in the carrot enzyme.