Large polymeric pigment

For each wine the following parameters (Y-variables) were measured total color (Aacet), total anthocyanins (TA), copigmentation (Copig), total polymeric pigment (EpP) at pH=3.6 (20), and small and large polymeric pigment (21). Values are reported as Absorbance units at 520 nm. 

Purines and pyrimidines are derived largely from amino acids. The biosynthesis of these precursors of DNA, RNA, and numerous coenzymes will be discussed in detail in Chapter 25. The reactive terminus of sphingosine, an intermediate in the synthesis of sphingolipids, comes from serine. Histamine, a potent vasodilator, is derived from histidine by decarboxylation. Tyrosine is a precursor of the hormones thyroxine (tetraiodothyronine) and epinephrine and of melanin, a complex polymeric pigment. The neurotransmitter serotonin (5-hydroxytryptamine) and the nicotinamide ring of NAD + are synthesized from tryptophan. Let us now consider in more detail three particularly important biochemicals derived from amino acids. 

Figure 3. Percentage of the total color contributed by the three classes of pigments found in a Syrah wine shortly after pressing. MP, monomeric pigments (anthocyanins) SPP, small polymeric pigments LPP, large polymeric...

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