Human cystatin D: cDNA cloning, characterization of the E. coli expressed inhibitor, and identification of the native protein in saliva
A cDNA coding for cystatin D, a human member of the cystatin protein family, has been cloned after specific amplification of reverse- transcribed parotid gland RNA. After replacing the segment encoding the putative 20-residue signal peptide with one encoding the Escherichia coli OmpA leader sequence, the cDNA was expressed in E. coli. The isolated recombinant protein exhibited Ki values of 1.2 nM