 The right-handed form, D-alanine, occurs in polypeptides in some bacterial cell walls and in some peptide antibiotics, and occurs in the tissues of many crustaceans and molluscs as an osmolyte.Alanine was first synthesized in 1850 when Adolph Strecker combined acetaldehyde and ammonia with hydrogen cyanide.The amino acid was named "Alanin" in German, in reference to aldehyde, with the infix "-an-" for ease of pronunciation, the German ending "-in" used in chemical compounds being analogous to English "-ine".