Proline stachydrine

Proline Stachydrine Stachys, orange leaves, lemon peel, alfalfa, Aspergillus oryzae... 

It has been shown that the biogenetic precursor of the pyrrolidine ring in plants is ornithine (8). In Medicago sativa L. the alkaloid stachydrine is stored in the seeds and appears to be actively synthesized only during the period of seed formation. At any rate, plants that are 19 weeks old are incapable of converting ornithine into stachydrine or even proline (9). Feeding the coenzyme pyridoxine together with labeled ornithine to the plant, however, results in the formation of radioactive proline, but no stachydrine is formed (10). The addition of methionine... 

The conversion of proline to stachydrine was based on experiments with Stachys palustris L., S. recta L., and Galeopsis ochrolev a Lam. (108). 

Experiments (although subject to some criticism) carried out by Klein and Linser (57) would indicate that stachydrine formation in the plant is markedly increased by injection into the hollow stalks of the possible precursor of the betaine. On the assumption that stachydrine could result from simple methylation of proline which in turn might be derived from glutamic acid via pyrrolidonecarboxylic acid, or from arginine via ornithine, injections were made of 1-2 % solutions of proline, ornithine dihydrochloride and sodium glutamate. The experiments carried out on Stachys palustris L., Stachys recta L., and Galeopsis ochroleuca Lam. revealed an apparent increase in stachydrine content as a result of these injections. 

Importance Pro is able to participate in a-helices to a much lower extent than other amino acids. It is thus a helix breaker of particular importance for the structure of proteins. Rotation about the amino peptide bond of proline is especially hindered the correct folding of Pro-containing proteins thus appears to be catalyzed by peptidylprolyl cis-fra/u-isomerases (rotamases, EC 5.2.1.8 see FK-506). On account of its presence in gluten, Pro is involved in the Maillard reaction resulting in the typical bread flavor. The inner salt (betaine) of I, l-dimethyl-P. is a widely distributed pyrrolidine alkaloid in plants, e.g., in woundwort (Stachys spp., stachydrin). 

In this chapter, prodigiosin, obtained from the cultured broth of Serratia marcescens stachydrine, isolated from Fabaceae plants and pyrrole-2-carboxyUc acid, isolated from the culture broth of Streptomyces sp. No. 82-85 are described. Regarding these alkaloids, it was established that labeled prohne is incorporated into these alkaloids. It was also determined that alanine and glycine are incorporated into prodigiosin, in addition to proline [1]. However, intact incorporation of proline into prodigiosin as a unit retaining the nitrc en atom was observed, and consequendy this alkaloid is described in this chapter. 

Stachydrine was isolated from Medicago sativa (Fabaceae), and it was established that this alkaloid was biosynthetically derived from proline. 

When either proline or hygric acid (N-methyl prohne) labeled with at the carbonyl carbon was incorporated, stachydrine labeled with at the carboxyl carbon position was obtained [1]. It was also shown that pro-line was transformed into stachydrine in mature plants. 

Namely, when labeled hygric acid was incorporated into young plants three weeks after germination, it was transformed into labeled stachydrine, whereas no labeled stachydrine was obtained by feeding labeled proline into the same plant. It seems that an enzyme that converts proline into hygric acid is absent or inactive in the young plant. 

Pyrrolidine alkaloids a group of Alkaloids (see) with simple structmes. P.a. are either derivatives of proline (e.g. stachydrin and its diastereoisomer, beto-nicin), or they are derived from a Af-methyl-2-alkyl-pyrrolidine (e.g. hygrin and cuskhydrin). The latter occur together with the tropane alkaloid with which they share the same biogenetic precursors, ornithine and acetate. 

Some of the configurational relationships established between different bases and amino acids have a possible biogenetic significance and may be briefly mentioned. Thus Karrer and Widmer (1925) methylated ( —)nicotine (I) on the pyridine nitrogen, (II) and oxidized this compound to l( —)hygrinic acid (III) which could be methylated to stachydrine this betaine is also formed from L-proline. Thus ( —)nicotine may be formed in nature from L-proline. 

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