EC Number   |
General Information |
Reference |
|---|
    2.6.1.45 | physiological function |
Arabidopsis thaliana serine:glyoxylate aminotransferase (AGT1) is a multifunctional class IV aminotransferase protein that catalyzes transamination reactions using L-serine, L-alanine, and L-asparagine as amino donors and glyoxylate, pyruvate, and hydroxypyruvate as amino acceptors. AGT1 is a peroxisomal aminotransferase with a central role in photorespiration. This enzyme catalyzes various aminotransferase reactions, including serine:glyoxylate, alanine:glyoxylate, and asparagine:glyoxylate transaminations |
759257 |
| 2.6.1.45 | malfunction |
elevated SGAT activity through transgenic overexpression of Flaveria pringlei SGAT causes clear changes in metabolism and interferes with photosynthetic CO2 uptake and biomass accumulation of Arabidopsis. The faster serine turnover during photorespiration progressively lowers day-time leaf serine contents and in turn induces the phosphoserine pathway. Transcriptional upregulation of this additional route of serine biosynthesis occurs already during the day but particularly at night, efficiently counteracting night-time serine depletion. Additionally, higher SGAT activity results in an increased use of asparagine as the external donor of amino groups to the photorespiratory pathway but does not alter leaf asparagine content at night. These results suggest leaf SGAT activity needs to be dynamically adjusted to ensure (i) variable flux through the photorespiratory pathway at a minimal consumption of asparagine and (ii) adequate serine levels for other cellular metabolism, phenotype analysis. Impact of excess SGAT activity on the photorespiratory pathway and photorespiratory nitrogen cycling, schematic overview |
-, 759565 |
| 2.6.1.45 | metabolism |
enzymic activity within the cell gradually decreases with the increase of cell density. Activity is significantly affected by light intensity and growth in presence of acetate as sole carbon source. Activity increases in presence of high oxygen concentrations and high carbon dioxide concentrations. An increase in oxygen concentration additionally results in a raise of cellular Gly/Ser ratio from 0.79 to 1.49 |
723450 |
| 2.6.1.45 | more |
in the enzyme crystal, another dimer related by noncrystallographic symmetry makes close interactions to form a tetramer mediated in part by an extra carboxyl-terminal helix conserved in plant homologues of AGT1. Residues Tyr35' and Arg36', entering the active site from the other subunits in the dimer, mediate interactions between AGT and L-serine when used as a substrate. Structural model of AGT1 and structure-function analysis, structure comparisons, detailed overview |
759257 |
| 2.6.1.45 | more |
influence of metabolites on the activity of recombinant serineglyoxylate aminotransferase, overview |
-, 758661 |
| 2.6.1.45 | physiological function |
overexpression in Lemna minor results in increased enzymic activity and decreased endogenous serine levels under salt stress, leading to enhanced protection against root abscission, higher maximum quantum yield of photosystem II, increased defense from cell damage as a result of improved cell membrane integrity, a decrease of reactive oxygen species accumulation, and a strengthened antioxidant system |
723401 |
| 2.6.1.45 | evolution |
phylogenetic analysis and tree |
-, 758661 |
| 2.6.1.45 | physiological function |
rice leaves usually show 3-4 times higher abundance of glutamate relative to serine, implicating that glutamate:glyoxylate aminotransferase GGAT may preferentially utilize glyoxylate to form glycine over serine:glyoxylate aminotransferase SGAT. When SGAT or GGAT activity is regulated by gene transformation or nitrogen deficiency, respectively, the glycine content is positively related to GGAT activities, while both serine and glycine contents are negatively related to SGAT activities, suggesting that GGAT preferentially catalyzes the conversion of glyoxylate into glycine while SGAT is mainly responsible for the transamination reaction of serine to hydroxypyruvate in the photorespiratory pathway of rice |
738913 |
| 2.6.1.45 | metabolism |
serine-glyoxylate aminotransferase (Sga) is the indicator enzyme of the serine pathway of assimilation of reduced C1 compounds |
-, 758661 |
| 2.6.1.45 | physiological function |
serine-glyoxylate aminotransferase (Sga) is the indicator enzyme of the serine pathway of assimilation of reduced C1 compounds. The Sga enzyme from the methanotroph catalyses the pyridoxal phosphate-dependent transfer of an amino group from serine to glyoxylate and pyruvate. Enzyme Sga is important in the serine cycle of type I methanotrophs and this pathway might be related to the removal of excess formaldehyde and/or energy regulation |
758661 |
