Fractional composition histidine

Fig. 4.16 The fractional composition of the protonated and deprotonated forms of histidine (His) in aqueous solution as a function of pH.

The amino add compositions of SCMKB fractions from a variety of mammalian fibers generally show similarities in being rich in half-cystine, proline, serine, and threonine. These four residues generally account for at least half the total residues. Residues such as lysine, histidine, tyrosine, and phenylalanine are generally low in SCMKB fractions, and methionine is usually absent [226,227]... 

Edible protein. The protein fraction of tomato seed is about 35% of the dry weight. This is higher than that of cottonseed which is about 20% protein (Morad et al., 1980). Three cultivars of tomato examined for amino acid composition had higher levels of lysine compared to commercial soybean meal (Rymal et al., 1974). Soymeal was higher in threonine, serine and histidine than tomato meal while both meals were low in methionine. Blended with low lysine protein sources, the tomato meal may be useful for balancing essential amino acids. The protein comprised about 33% of the seed (Bertoni et al., 1963). The limiting amino acids in tomato seed are methionine and cystine. 

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