Lysine alkaloids derived from

The tobacco alkaloids, especially nicotine, are derived from nicotinic acid (see page 311) but also contain a pyrrolidine ring system derived from ornithine as a portion of their structure. 

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There are many pyrrolidine alkaloids derived from ornithine and another large family of piperidine alkaloids derived from lysine by similar pathways involving... 

In further consideration of the biosynthesis of the piperidine alkaloids the question of the significance of the incorporation of cadaverine must be answered. Accordingly further research has been directed to this point and it has been shown that cadaverine is a normal component of S. acre, that it is a specific precursor of sedamine (20), and that it is formed from lysine at the same time as sedamine. It follows then that any scheme for the biosynthesis of the piperidine alkaloids which does not accommodate cadaverine as a normal component is unrealistic An eminently reasonable hypothesis which fits all the evidence is shown in Scheme 1 it was anticipated in last year s Report. For those alkaloids derived from lysine without the intervention of a symmetrical intermediate, cadaverine formed by decarboxylation of lysine must remain enzyme-bound and therefore unsymmetrical. Exogenous cadaverine enters the pathway at this point by absorption on to the enzyme to give (29). In order to explain the incorporation of lysine into some alkaloids by way of a symmetrization step it is necessary only to postulate equilibration of bound with unbound cadaverine. The proposal that pyridoxal phosphate is involved in this pathway is more than mechanistically attractive, for L-lysinedecarboxylase (EC 4.1.1.18, L-lysine carboxy-lyase) and diamine oxidase [EC 1.4.3.6, diamine oxygen oxidoreductase (deaminating)], the two enzymes whose participation in the conversion of lysine into A -piperideine (30) is likely, both require pyridoxal phosphate as a co-factor. 

Nicotine and anabasine are considered to be alkaloids derived firom nicotinic acid (pyridine-3-carboxylic acid).These alkaloids can be also classified as derived from ornithine and lysine, respectively. Therefore, these alkaloids are described in Chapter 10.1 (as alkaloids derived from nicotinic acid), in Chapter 3.1 (alkaloids derived from ornithine and arginine), and in Chapter 4.3 (alkaloids derived from lysine). However, such exceptions are relatively rare if the classification of alkaloids is conducted based on their biosynthetic origin. 

Among the alkaloids derived from lysine, some are alkaloids in which lysine was incorporated intact, and others are alkaloids in which cadaverine, the symmetrical precursor derived from lysine by decarboxylation, was incorporated. 

Alkaloids Derived from Lysine Piperidine Alkaloids < <... 

The piperidine, quinolizidine, indolizidine alkaloids derived from lysine are belonging to so-called tme alkaloids because their nitrogen atoms originate from an amino acid, and in general, the carbon skeleton of the particular amino acid precursor is also largely retained intact in the alkaloid structure. Relatively few amino acid precursors are actually involved in alkaloid biosynthesis, the principal ones being also lysine [1]. 

Alkaloids Derived from Lysine Quinolizidine (a Focus on Lupin Alkaloids)... 

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