Scientists have discovered in the common weed thale cress a new substance with an important link to human brain chemistry responsible for turning off plaque formation in Alzheimer’s disease.
The research has just been published in the top US journal PNAS (Proceedings of the National Academy of Science).
It was carried out by an international team led by the University of Stockholm and included La Trobe University biochemist Professor Jim Whelan.
Professor Whelan says the work identified and characterized a new enzyme, an organelle OligoPeptidase called OOP.
The enzyme was found in mitochondria and chloroplasts, tiny but highly important energy generation centres in the cells of thale cress. Also known as Arabidopsis, the plant is a favourite model organism of molecular biologists.
‘We found that the OOP destroys small peptides in the plant’s cell that would otherwise become toxic to the cell,’ says Professor Whelan.
He says documenting the biological pathways which lead to enzymes breaking down proteins and peptides is essential to understanding disease in animals as well plants.
Critical to study the human variant
‘For example an enzyme known as Presequence Protease, which was also first extensively characterised in plants, can degrade the peptide beta-amyloid which forms insoluble fibres, or plaques in the brain of Alzheimer’s patients.
‘We believe OOP and this Presequence Protease could co-operate to completely break down harmful peptides that accumulate and adversely affect mitochondrial activities.’
Hence in order to combat Alzheimer’s disease and other age-related diseases, he says it is critical to study the human variant of OOP and examine its role in the degradation of amyloid-beta peptide.
Professor Whelan is a specialist in plant energy metabolism. He works at the new AgrBio Centre on La Trobe’s Melbourne campus and is also a member of the Australian Research Centre of Excellence in Plant Energy Biology.
The PNAS article is the result of collaboration between biochemistry, biophysics and neurochemistry researchers at Stockholm University, SciLifeLab at the Karolinska Institute, La Trobe University and the University of Western Australia.