GA20oksidaz

GA20oksidaz refers to the GA20-oxidases, a family of plant enzymes commonly abbreviated GA20ox. These enzymes are part of the gibberellin biosynthesis pathway and are responsible for converting early gibberellin precursors into forms that can be further processed into bioactive gibberellins. The term GA20oksidaz reflects a transliteration used in some languages and corresponds to the GA20-oxidase enzymes studied in many plant species.

Biochemically, GA20-oxidases are 2-oxoglutarate-dependent dioxygenases that catalyze oxidative steps at the C-20 position of gibberellin precursors. They typically act on substrates such as GA12 and related intermediates to produce GA9 and GA20, which are then substrates for GA3-oxidases to yield the bioactive GA1 and GA4. Through these reactions, GA20ox enzymes help regulate the pool of active and inactive gibberellins and thereby influence growth and development.

Gene family and regulation: In many plants, GA20ox is encoded by multiple genes, forming a small gene family (for example, Arabidopsis thaliana has several GA20ox genes with partly overlapping expression patterns). Expression of GA20ox genes is tissue-specific and developmentally regulated, and they are subject to feedback control by gibberellin levels and various environmental cues such as light and temperature. The enzymes can have distinct expression profiles in meristems, young leaves, and developing seeds, contributing to tissue-specific GA biosynthesis.

Localization and structure: GA20ox enzymes are soluble dioxygenases, typically localized to the cytosol or associated with cellular membranes, and require iron, 2-oxoglutarate, and ascorbate as cofactors for activity.

Impact and applications: Because GA20ox activity influences plant height and developmental timing, these enzymes are of interest in agriculture and plant biotechnology for modulating growth, vigor, and yield. Altered GA20ox activity can lead to dwarfing or taller phenotypes, depending on the plant and context.