반응 #1466404

반응 방정식

ammonium formate

leucine

formate

ammonia

NAD+

ammonia

charcoal

2-keto-3,3-dimethyl pentanoic acid sodium salt

→

(S)-3-methyl-isoleucine

용매

water

반응 조건

후처리

1. 1
   workup.DISSOLUTIONdissolve
2. 2
   기타is set to 32° C
3. 3
   기타During the reaction the system
4. 4
   workup.WAITAfter at most 72 h it is demonstrated via determination of degree of conversion by HPLC that the reaction
5. 5
   농축The almost colourless solution is concentrated at a rotary evaporator
6. 6
   기타the amino acid is crystallized
7. 7
   기타is separated via a funnel
8. 8
   세척is washed three times with little ethanol
9. 9
   기타is dried overnight under vacuum at 50° C.

실험 절차

6.3 g (0.1 mole) ammonium formate and 1.67 g (10 mmoles) 2-keto-3,3-dimethyl pentanoic acid sodium salt are suspended in 80 ml of water, the pH value is adjusted with ammonia to 8.2, so that the solids dissolve and the volume is adjusted to 100 ml. Subsequently, 14.34 mg (0.02 mmole) NAD+.3H2O cofactor as well as 800 U of leucine dehydrogenase (LeuDH) and 500 U of formate dehydrogenase (FDH) are added. The temperature is set to 32° C. During the reaction the system is gently stirred and the pH value is adjusted to 8.2 via a pH stat unit. After at most 72 h it is demonstrated via determination of degree of conversion by HPLC that the reaction is finished. The reaction solution is adjusted to pH 9.5 with ammonia and subsequently clarified with 2% active charcoal. The almost colourless solution is concentrated at a rotary evaporator, the amino acid is crystallized, is separated via a funnel, is washed three times with little ethanol and is dried overnight under vacuum at 50° C.

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