Finley J W, Friedman M
Adv Exp Med Biol. 1977;86B:123-30. doi: 10.1007/978-1-4757-9113-6_8.
Intense heat treatment of proteins at high pH favors formation of transient, reactive intermediates derived from serine and cystine. The postulated dehydroalanine intermediate reacts further with the epsilon-amino groups side chains and sulfhydryl groups of cysteine residues to form derivatives of lysinoalanine and lanthionine. Recent studies indicate that besides these crosslinked products, several others are formed, by reaction of histidine, arginine, and possibly other residues. For this reason, caution should be exercised in assigning the prelysine peak(s) of an amino acid chromatogram to lysinoalanine. These results suggest that unnatural amino acid derivatives, other than lysinoalanine, may also contribute to the toxic effects reported from studies in which alkali-treated protein was fed to rats.
在高pH值下对蛋白质进行强烈热处理有利于形成源自丝氨酸和胱氨酸的瞬时反应性中间体。假定的脱氢丙氨酸中间体会进一步与半胱氨酸残基的ε-氨基侧链和巯基反应，形成赖氨酰丙氨酸和羊毛硫氨酸的衍生物。最近的研究表明，除了这些交联产物外，组氨酸、精氨酸以及可能的其他残基反应还会形成其他几种产物。因此，在将氨基酸色谱图中的前赖氨酸峰归为赖氨酰丙氨酸时应谨慎。这些结果表明，除赖氨酰丙氨酸外，非天然氨基酸衍生物也可能导致在给大鼠喂食碱处理蛋白质的研究中所报道的毒性作用。
