Prolines synthesis

Hare, P.D., Cress, W.A., and Van Staden, J., Proline synthesis and degradation a model system for elucidating stress-related signal transduction, J. Exp. Bot, 50, 413,... 

On the basis of the success of these initial reports on the proline-catalyzed intramolecular aldol reaction several groups focused on extending this type of synthesis to bicyclic products bearing angular substituents other than methyl and ethyl reported earlier [97-101]. Preparation of bicyclic systems with protected hydroxymethyl substituents, e.g. 99, was reported by Uda et al. (Scheme 6.46, Eq. 1) [113, 114]. As a selected example, the aldol adduct 99 was formed in 70% yield and with 75% ee in the presence of one equivalent of L-proline. Synthesis of a related product with an angular phenylthio substituent, 101, was described by Watt and co-workers (Scheme 6.46, Eq. 2) [115]. After intramolecular proline-catalyzed aldol reaction, dehydration of the ketol intermediate, and subsequent recrystallization... 

The most widely recognized physiological action of the insect AKH/HGHs is to mobilize lipids or carbohydrates from fat body reserves for use as energy substrates by peripheral tissues. In Leptinotarsa decemlineata, proline is the main substrate for flight muscle metabolism (16), and Lom-AKH-I promotes fat body proline synthesis... 

We have already described the biosynthesis of glutamate and glutamine. Proline is a cyclized derivative of glutamate (Fig. 22-10). In the first step of proline synthesis, ATP reacts with the y-carboxyl group of glutamate to form an acyl phosphate, which is reduced by NADPH or NADH to glutamate y-semialdehyde. This intermediate undergoes rapid spontaneous cychzation and is then reduced further to yield proline. 

Arginine Synthesis, Proline Synthesis, and Related Processes... 

Fig. 2. Proline synthesis from glutamic acid. The details of the reactions are in Table ...

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