Structure-function relationships of beta-D-glucan endo- and exohydrolases from higher plants

(1→3),(1→4)-β-D-Glucans represent an important component of cell walls in the Poaceae family of higher plants. A number of glycoside endo- and exohydrolases is required for the depolymerization of (1→3),(1→4)-β-Dglucans in germinated grain or for the partial hydrolysis of the polysaccharide in elongating vegetative tissues. The enzymes include (1→3),(1→4)-β-D-glucan endohydrolases (EC 3.2.1.73), which are classified as family 17 glycoside hydrolases, (1→4)-β-D-glucan glucohydrolases (family 1) and β-D-glucan exohydrolases (family 3). Kinetic analyses of hydrolytic reactions enable the definition of action patterns, the thermodynamics of substrate binding, and the construction of subsite maps. Mechanism-based inhibitors and substrate analogues have been used to study the spatial orientation of the substrate in the active sites of the enzymes, at the atomic level. The inhibitors and substrate analogues also allow us to define the catalytic mechanisms of the enzymes and to identify catalytic amino acid residues. Three-dimensional structures of (1→3),(1→4)-β-D-glucan endohydrolases, (1→4)- β-D-glucan glucohydrolases and β-D-glucan exohydrolases are available or can be reliably modelled from the crystal structures of related enzymes. Substrate analogues have been diffused into crystals for solving of the threedimensional structures of enzyme-substrate complexes. This information provides valuable insights into potential biological roles of the enzymes in the degradation of the barley (1→3),(1→4)-β-D-glucans during endosperm mobilization and in cell elongation.Maria Hrmova and Geoffrey B. Finche

Structure-function relationships of β-D-glucan endo- and exohydrolases from higher plants

Reprinted from Plant Molecular Biology, Volume 47 (1, 11),2001Maria Hrmova, Geoffrey B. Finche

Linseed essential oil - source of lipids as active ingredients for pharmaceuticals and nutraceuticals

Linseed - also known as flaxseed - is known for its beneficial effects on animal health attributed to its composition. Linseed comprises linoleic and ?-linolenic fatty acids, various dietary fibers and lignans, which are beneficial to health because they reduce the risk of cardiovascular diseases, as well as cancer, decreasing the levels of cholesterol and relaxing the smooth muscle cells in arteries increasing the blood flow. Essential fatty acids from flax participate in several metabolic processes of the cell, not only as structuring components of the cell membrane but also as storage lipids. Flax, being considered a functional food, can be consumed in a variety of ways, including seeds, oil or flour, contributing to basic nutrition. Several formulations containing flax are available on the market in the form of e.g. capsules and microencapsulated powders having potential as nutraceuticals. This paper revises the different lipid classes found in flaxseeds and their genomics. It also discusses the beneficial effects of flax and flaxseed oil and their biological advantages as ingredients in pharmaceuticals and in nutraceuticals products.The authors wish to acknowledge the financial support from the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the Partnership Agreement PT2020 for the project M-ERA-NET/0004/2015-PAIRED.info:eu-repo/semantics/publishedVersio