Cystine manufacture

Production by Isolation. Natural cysteine and cystine have been manufactured by hydrolysis and isolation from keratin protein, eg, hair and feathers. Today the principal manufacturing of cysteine depends on enzymatic production that was developed in the 1970s (213). 

There are 22 different AAs in the body of the bird, 10 of which are essential AA (EAA arginine, methionine, histidine, phenylalanine, isoleucine, leucine, lysine, threonine, tryptophan and valine), i.e. cannot be manufactured by the body and must be derived from the diet. Cystine and tyrosine are semi-essential in that they can be synthesized from methionine and phenyla-... 

Biochemicals, Nottingham, U.K.). All are advocated by the manufacturers for the analysis of micro-cystins in water, and several microcystin variants have been tested using these systems. 

High pH values and temperatures and prolonged processes favor production of lysinoalanine in many proteins. This reaction compound, formed mostly at the expense of lysine and cystine in soy protein (Savoie and Parent, 1983), causes neph-rocytomegaly in rats (Karayianis et al., 1979). While the effects of lysinoalanine on humans are not known (Struthers, 1981), conditions favoring its production (Freid-man, 1982) should be minimized. Lysinoalanine became a perceived problem when SPI produced for industrial applications in biobased products inadvertently got into food lysinoalanine is not a current problem to manufacturers of soy protein food ingredients. 

Diamalt, A.G. (1974). Effect of L-cysteine and L-cystine on the manufacture and improvement of foods. Lebensro. Wiss. Tech-nol. 2. 64-69. 

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