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Patchornik & Sokolovsky (1964) isolated a new amino acid from both the native and dinitrophenylated forms of ribonuclease after these had been treated with alkali. The amino acid was named 'lysinoalanine', since it was formed by reaction between lysine residues and residues of dehydroalanine, which were said to arise from residues of cystine, or of S-dinitrophenylated cystine, by ,Belimination. The discovery was confirmed by Bohak (1964), who established the identity of LAL* by oxidative studies and confirmed it by synthesis. He also demonstrated that all proteins containing lysine and cystine residues did not yield LAL on treatment with alkali, whereas phosvitin, with neither cystine nor cysteine residues in its structure, suffered conversion of almost 80% of its lysine residues into LAL when so treated. In this case Bohak (1964) claimed that the dehydroalanine residues required were formed from phosphoserine residues by ,8-elimination. Despite these findings he tentatively suggested that LAL forms most readily when the sequence-CyS-Lys-is present in a protein, and perhaps also when half-cystine and lysine residues are in other spatial relationships. Ziegler (1964) found LAL in alkali-treated wool, and suggested that it most probably constituted the cross-link between lysine residues and modified