## Abstract We have developed methods for the preparation of L‐glutamic acid, isotopically labeled with ^13^C, using commercially available purified enzymes. The procedure is sufficiently versatile that L‐glutamic acid may be labeled at any carbons or any combination of carbons using ^13^C‐labeled
Synthesis of specifically stable-isotope-labeled l-proline via L-glutamic acid
✍ Scribed by J. J. Cappon; G. A. M. van der Walle; P. J. E. Verdegem; J. Raap; J. Lugtenburg
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 725 KB
- Volume
- 111
- Category
- Article
- ISSN
- 0165-0513
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
(3,4‐^13^C~2~)‐L‐proline and (^15^N)‐L‐proline were prepared from the correspondingly labeled L‐glumatic acids via a single scheme in high yield and on a gram scale. The synthetic route is based on the ring closure of L‐glutamic acid to L‐5‐oxoproline and the selective reduction of the 5‐amide function, without interference with the 2‐carboxylate function and the asymmetric center. The selective reduction is effected by first converting the amide into the corresponding thioamide and subsequently reducing the thioamide to the amine using tributyltin hydride, in combination with protection and deprotection steps. In earlier work we described the preparation of L‐glutamic acid isotopically labeled at any position or combination of positions starting from simple highly enriched synthons. The synthetic scheme in this publication makes L‐proline, ^13^C‐ or ^15^N‐labeled at any position or combination of positions, easily available. The labeled L‐prolines are characterized by ^1^H‐, ^13^C‐ and ^15^N‐NMR and mass spectrometry.
📜 SIMILAR VOLUMES
The related tripeptides glycyl-l-prolyl-l-glutamic acid (GPE) and glycyl-l-2methylprolyl-l-glutamic acid (G-2-MePE) were labelled with commercially available [1,2,3,4,5-13 C 5 , 2-15 N 1 ]-l-glutamic acid in 3 steps in excellent overall yield with high isotope incorporation. A related cyclic dipepti
## Abstract Tryptophan synthase catalyzes the nucleophilic replacement of the hydroxyl group at C‐3 of L‐serine. This enzyme can use benzyl mercaptan as a nucleophile in the conversion of serine to S‐benzyl‐L‐cysteine which is deblocked by treatment with sodium in liquid ammonia to yield L‐cysteine