Chemical element "Sb" (stibium) for antimony. Chemical symbols are understood internationally when element names might require translation. There have sometimes been differences in the past. For example, Germans in the past have used "J" (for the alternate name Jod) for iodine, but now use "I" and "Iod". The first letter of a chemical symbol is always capitalized, as in the preceding examples, and the subsequent letters, if any, are always lower case (small letters). Thus, the symbols for californium and einsteinium are Cf and Es. There are also symbols in chemical equations for groups of chemical elements, for example in comparative formulas.
Chemical ligation with an N-terminal Ser or Thr residue. The chemoselective reaction between the peptide SAL ester and 1,2-hydroxylamine group of Ser or Thr leads to the formation of an N,O-benzylidene acetal linked intermediate, which undergoes acidolysis to afford a natural peptidic Xaa-Ser/Thr linkage. This method does not involve the use of unnatural amino acids, and it is simple to operate. Ser/Thr ligation provides a complementary method for protein chemical synthesis and semisynthesis. Schnölzer M, Kent SB. 1992, "Constructing proteins by dovetailing unprotected synthetic peptides: backbone-engineered HIV protease." "Science". 256:221-5 Dawson PE, Muir TW, Clark-Lewis I, Kent SB. 1994, "Synthesis of proteins