Human protein S cDNA encodes Phe-16 and Tyr 222 in consensus sequences for the post-translational processing.

Partial cDNAs coding for human protein S were isolated from a pUC9 human liver cDNA library. Together, the overlapping clones span a (partial) 5'-non-coding region, and the complete protein S coding and 3'-untranslated regions. The derived amino acid sequence deviates at five positions from two previously reported protein S sequences. Two of these differences (Phe instead of Leu at position -16 and Tyr instead of Asp at position 222) are found in regions that are important for the post-translational modification of protein S, the gamma-carboxylation of glutamic acid and the hydroxylation of asparagine, respectively.