THE RELATION OF MOLECULAR CONFIGURATION TO THE RATE OF DEAMINATION OF SYMPATHOMIMETIC AMINES BY AMINASE

¹ From the Department of Physiology, University of Wisconsin Medical School, Madison

From our observations we have offered the following generalizations for the relation of molecular structure to the rate of oxidative deamination of sympathomimetic amines in the presence of aminase.

1. Where a difference in rate was measurable, secondary amino compounds were oxidized more rapidly than the corresponding primary amino homolog. This difference in rate was minimized when there existed in the molecule a para phenolic ring or a 3,4-dihydroxy catechol nucleus.

2. Where there existed an asymmetrical beta carbon atom in the side chain, due either to a single methyl or hydroxyl group, the rate of deamination of the primary or secondary amino group was increased. This generalization together with the next one was limited to compounds having no hydroxyl groups on the aromatic nucleus.

3. Where two methyl groups existed on the beta carbon atom, reducing its asymmetry, the rate of deamination was markedly reduced.

4. Tertiary amino compounds were not deaminated to any measureable extent.

5. Where a para phenolic radical existed in the molecule the rate of oxidative deamination was markedly more rapid than for its homolog having no phenolic group.

6. If the phenolic group was shifted from the para to the ortho position the rate of deamination was markedly reduced whereas the order of the reaction remained the same.

7. There was an increase in rate of deamination as one passed from the nonphenlic through the para phenolic to the 3,4-dihydroxy phenolic compounds having an identical side chain.

8. Where an aliphatic hydroxyl or ketone group was introduced on the carbon atom beta to the amino group of the phenolic pressor amines the rate of deamination was reduced. This reduction in rate was greatest for the ketone of adrenalin, when one compared the rate of oxygen uptake for epinine, adrenalin and adrenalone (adrenalin ketone).

Wherever posssible we have interpreted these reaction rates in terms of variations of intramolecular electronic forces set up by substitutions into the fundamental phenylethylamine structure.

This article has been cited by other articles:

				Wm. M. Govier, B. G. Howes, and A. J. Gibbons The Oxidative Deamination of Serotonin and Other 3-(beta-Aminoethyl)-indoles by Monamine Oxidase and the Effect of These Compounds on the Deamination of Tyramine Science, November 13, 1953; 118(3072): 596 - 597. [PDF]