Glutamine Synthetase (GST) グルタミンシンセターゼ

  • 臨床診断用酵素

臨床検査において、アンモニアおよびATPの測定に利用されます。

由来 microorganism
系統名

L-Glutamate : ammonia ligase (ADP-forming)

EC 番号 6.3.1.2
反応式

ATP + L-Glutamate + NH3→→→ ADP + Orthophosphate + L-Glutamine

仕様

Appearance light yellow lyophilizate
Activity ≧15.0 U/mg lyophilizate
Contaminants catalase <0.5%
Stabilizer sucrose
Storage below -20℃

特性

Molecular weight ca. 900 kDa (gel filtration)
Structure 57 kDa (SDS-PAGE)
Isoelectric point 6.5
Michaelis constant 1.5×10-2M (L-glutamate)
1.3×10-4M (ammonia)
8.7×10-4M (ATP)
pH Optimum 7.0
pH Stability 6.5–9.5
Optimum temperature 60℃
Thermal stability below 40℃
Stability (liquid form) stable at 20℃ for at least two weeks
Stability (powder form) stable at 37℃ for at least one month
Inhibitors methionine sulfoximine, carbamyl phosphate
Activators Mg2+,Mn2+
Specificity L-glutamate (100), D-glutamate (0.8)
NH₃(100), NH₂OH (12)
ATP (100), GTP (2.5)

アプリケーション

The enzyme is useful for the determination of ammonia and ATP in clinical analysis.

参考文献

Ebner, E. et al., “Methods in Enzymology,” Vol. 17A, Academic Press, New York, 1970, pp. 910–922.

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