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Plant Sample Preparation for Nucleoside/Nucleotide Content Measurement with An HPLC-MS/MS
Published on: February 24, 2021
Putrescine N-methyltransferase--the start for alkaloids
Stefan Biastoff1, Wolfgang Brandt, Birgit Dräger
1Institute of Pharmacy, Faculty of Natural Sciences I, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany.
Phytochemistry
|August 5, 2009
Summary
Putrescine N-methyltransferase (PMT) catalyzes essential alkaloid biosynthesis. This enzyme likely evolved from spermidine synthase, with distinct active sites shaping its specialized function.
Area of Science:
- Biochemistry
- Plant Molecular Biology
- Enzymology
Background:
- Putrescine N-methyltransferase (PMT) is key in synthesizing nicotine, tropane, and nortropane alkaloids.
- N-methylputrescine, the product of PMT activity, is the initial metabolite in these alkaloid pathways.
Purpose of the Study:
- To investigate the evolutionary origins and enzymatic properties of Putrescine N-methyltransferase (PMT).
- To compare PMT with related enzymes like spermidine synthase.
Main Methods:
- Cloning of PMT cDNA sequences from various plant species (Solanaceae, Convolvulaceae).
- Synthesis of PMT proteins in Escherichia coli for functional studies.
- Enzyme activity assays using HPLC and a colorimetric method measuring S-adenosylhomocysteine.
Main Results:
- PMT cDNA sequences show resemblance to plant spermidine synthases but little to other methyltransferases.
- Phylogenetic analysis indicates PMT evolved from spermidine synthase early in angiosperm development.
- Both PMT and spermidine synthase share structural similarities and bind similar substrates, but possess distinct active sites.
Conclusions:
- Putrescine N-methyltransferase (PMT) likely originated from spermidine synthase through evolutionary divergence.
- Differential evolution of active sites accounts for PMT's specific role in alkaloid biosynthesis.
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