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 white to light yellow lyophilizate
Activity ≧15.0 U/mg
Contaminants Catalase ≦0.5 U/U%
Stabilizer sucrose
Storage condition 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 ca. 7.0
pH Stability 6.5–9.5
Optimum temperature 60℃
Thermal stability below 40℃
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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