Branched C and C7 Amino-acids

Suketa, M. Sugii, and T. Suzuki, Ckem. and Pharm. Bull. (Japan), 1970,18, 249. 

4-Methyleneglutamic acid and 4-amino-2-methylenebutyric acid occur in tulips. The lactone of 4-hydroxy-2-methylenebutyric acid, isolated from tulip bulbs, supposedly derives from one of these amino-acids. Incorporation of labelled acetate and pyruvic acid into the lactone has been taken as evidence of a condensation reaction, although the results are also in keeping with the operation of the above-mentioned exchange reaction. 

The biosynthesis of N,3,4-trimethylpentanoic acid in a Streptomyces species has been shown to proceed from leucine with transfer of two methyl groups from methionine.  

Imino-aclds.—The transformation of DL-[6- H,6- C]lysine into pipecolic add with retention of tritium has been demonstrated in rats, in Neurospora crassa, in kidney beans, and in Sedum acre, and into the piperidine alkaloid sedamine with retention of tritium in S. acre. Correspondingly, [2- H,6- C]lysine is incorporated into pipecolic acid in kidney beans and S. acre with loss of tritium, indicating that the transformation takes place via 6-amino-2-keto-hexanoic acid and A -piperideine-2-carboxylic acid. In S. acre, however. 

DL-[2- H.6- C]lysine was incorporated into sedamine without loss of tritium, indicating an alternative pathway in plants from lysine to sedamine and other alkaloids. In this connection it is of interest that D-lysine is transformed into pipecolic acid whereas L-lysine is converted into the alkaloid anabasin in Nicotiana glauca. Analogously, in Pseudomonas putida, L-lysine is transformed into S-aminopentanoic acid but D-lysine into pipecolic acid. The latter transformation has also been observed in corn and ryegrass seedlings.  

---