Signalling molecules amino acid derivatives

Amino acid derivatives include the thyroid hormones, catecholamines (e.g. adrenaline (epinephrine)) and dopamine, neurotransmitters such as y-aminobutyric acid (GABA) and noradrenaline (norepinephrine). All of these signalling molecules retain... 

In terms of their chemical structures, signalling molecules fall into five main categories (i) peptides, (ii) steroids, (iii) amino acids and their derivatives, (iv) fatty acid derivatives, and (v) nucleotides. 

The plane of the paper is a plane of symmetry for both these CH2 groups in the way they are drawn here. The iV-benzyl derivatives of the other amino acids are quite different. Each shows an AB signal for the NCH2Ph group because these molecules have stereogenic centres and there are no planes of symmetry, The Hs of the... 

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