|Gene:||SAMS1||Accession Number: G-9126 (MetaCyc)|
Species: Catharanthus roseus
SAM synthetase is encoded by a small gene family of three members in C. roseus. The three genes are differentially expressed in seedlings, and in cell cultures treated with salt stress, nutrient stress and fungal elicitor. The three isoenzymes however have similar properties such as subcellular location, protein size, Kms for substrates, optimum pH and temperature, dependence on cations, inhibition by end products and other metabolites.
Molecular Weight of Polypeptide: 45 kD (experimental) [Schroder97 ]
Relationship Links: Entrez-Nucleotide:PART-OF:Z71271
|Cellular Component:||GO:0005737 - cytoplasm [Schroder97]|
Enzymatic reaction of: S-adenosylmethionine synthetase
Synonyms: methionine adenosyltransferase
EC Number: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
The reaction is favored in the direction shown.
In Pathways: S-adenosyl-L-methionine cycle II
The enzyme is strictly dependent on divalent cations such as Mg2+, Mn2+ and Co2+. It also requires monovalent cations, such as K+, NH4+, for optimum activity. The reaction intermediate, PPPi, is a strong inhibitor with Ki of 35 uM.
Inhibitors (Unknown Mechanism): PPPi [Schroder97] , S-adenosyl-L-methionine [Schroder97] , diphosphate [Schroder97] , phosphate [Schroder97] , GTP [Schroder97] , CTP [Schroder97] , ADP [Schroder97] , cycloleucine [Schroder97] , L-ethionine [Schroder97]
T(opt): 37-45 °C [Schroder97]
pH(opt): 7-8.3 [Schroder97]
Schroder97: Schroder G, Eichel J, Breinig S, Schroder J (1997). "Three differentially expressed S-adenosylmethionine synthetases from Catharanthus roseus: molecular and functional characterization." Plant Mol Biol 33(2);211-22. PMID: 9037140
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