Abstract

We have now access to the sequences of all genes existing in a plant, but the catalytic activities of the encoded enzymatic proteins are only known for a minority of these genes. For sure, there are many enzymes that have not been described at all by biochemists that hide in these sequences. Although it is now possible to order T-DNA insert mutants of virtually any selected gene in Arabidopsis, most of these mutants give no obvious phenotype that can aid in elucidating the function of the gene. In this presentation we show that there are a great number of transacylase enzymes present in plants which activities are so minor in most tissues that they have not previously caught the attention by the plant biochemists. However, by utilising recent developed molecular genetic tools in combination with intricate biochemical studies, we can now start to characterize these enzymes and show how they interact with other enzymes in the ever more complicated web of plant lipid metabolism. A simple experiment in order to demonstrate the presence of numerous transacylase enzymes can be done by incubation of plant microsomal membranes with phospholipids containing radioactive acyl groups for an hour at 30oC. After extraction of the lipids, separation on TLC and monitoring the distribution of radioactivity among different lipid classes, we can observe a great number of novel spots of radioactivity, each of them being a result of enzymatic activity. For most of these reactions, the nature of the responsible enzyme is completely unknown. We here present results on the characterization of five of these enzymes and identification of three of their encoding genes. We further show the value of using T-DNA mutants in order to reveal the presence of novel enzymes which catalytic activities are ‘masked’ by other enzyme activities

Published in

Conference

16th International Plant Lipid Symposium

SLU Authors

• Stymne, Sten

  • Department of Crop Science, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science


Permanent link to this page (URI)

https://res.slu.se/id/publ/5384