This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Biosynthesis → Amino Acids Biosynthesis → Proteinogenic Amino Acids Biosynthesis → Glycine Biosynthesis|
Some taxa known to possess this pathway include : Saccharomyces cerevisiae
When the cells are grown with glucose as the carbon source, two alternative pathways operate. In one pathway L-threonine aldolase, encoded by GLY1, produces glycine from L-threonine (which is produced from the glycolytic intermediate oxaloacetate) (see glycine biosynthesis IV). In the other pathway glycine is formed from L-serine (a product of 3-phospho-D-glycerate, another glycolytic intermediate) via two serine hydroxymethyltransferases - a cytosolic enzyme (SHMT2) and a mitochondrial enzyme (SHMT1) (see glycine biosynthesis I). The two isoforms are reported to work in opposite directions, depending on the culture conditions [Kastanos97].
When the cells are grown with a non-fermentable carbon source, such as ethanol and acetate, glycine is produced from glyoxylate, a product of the glyoxylate cycle, by the enzyme alanine--glyoxylate aminotransferase 1 (see glycine biosynthesis III).
About This Pathway
alanine--glyoxylate aminotransferase 1 is one of three different enzymes used for glycine synthesis in Saccharomyces cerevisiae. This enzyme is active only during growth on non-fermentable carbon sources, and enables Saccharomyces cerevisiae to grow on ethanol as sole carbon source, by alleviating the need for glycolytic intermediates as the precursors for glycine [Schlosser04].
Alanine--glyoxylate transaminase is widely distributed, and has been documented in archaea, bacteria and eukaryota.
Kastanos97: Kastanos EK, Woldman YY, Appling DR (1997). "Role of mitochondrial and cytoplasmic serine hydroxymethyltransferase isozymes in de novo purine synthesis in Saccharomyces cerevisiae." Biochemistry 36(48);14956-64. PMID: 9398220
Schlosser04: Schlosser T, Gatgens C, Weber U, Stahmann KP (2004). "Alanine : glyoxylate aminotransferase of Saccharomyces cerevisiae-encoding gene AGX1 and metabolic significance." Yeast 21(1);63-73. PMID: 14745783
Liepman03: Liepman AH, Olsen LJ (2003). "Alanine aminotransferase homologs catalyze the glutamate:glyoxylate aminotransferase reaction in peroxisomes of Arabidopsis." Plant Physiol 131(1);215-27. PMID: 12529529
Okuno80: Okuno E, Minatogawa Y, Nakamura M, Kamoda N, Nakanishi J, Makino M, Kido R (1980). "Crystallization and characterization of human liver kynurenine--glyoxylate aminotransferase. Identity with alanine--glyoxylate aminotransferase and serine--pyruvate aminotransferase." Biochem J 189(3);581-90. PMID: 6783036
Rodionov10: Rodionov RN, Murry DJ, Vaulman SF, Stevens JW, Lentz SR (2010). "Human alanine-glyoxylate aminotransferase 2 lowers asymmetric dimethylarginine and protects from inhibition of nitric oxide production." J Biol Chem 285(8);5385-91. PMID: 20018850
Takada85: Takada Y, Noguchi T (1985). "Characteristics of alanine: glyoxylate aminotransferase from Saccharomyces cerevisiae, a regulatory enzyme in the glyoxylate pathway of glycine and serine biosynthesis from tricarboxylic acid-cycle intermediates." Biochem J 231(1);157-63. PMID: 3933486
©2016 SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493