Department of Medicine, Veterans' Administration Medical Center, San Francisco, California 94121.
We have isolated and determined the nucleotide sequence of overlapping cDNA clones, representing the entire structural gene for pig thyroid peroxidase. The protein coding region extends from an ATG residue at base 252 to a termination codon at base 3030, coding for a 100.4-kDa apoprotein of 926 amino acids. The derived amino acid composition agrees well with the experimentally determined amino acid composition of purified pig thyroid peroxidase. Five potential glycosylation sites are present in the protein. Potential membrane spanning regions are present at the amino-terminal end (1-23) and near the carboxyl-terminal end (845-870) of the protein. These data indicate that pig thyroid peroxidase is synthesized as a single polypeptide that is membrane-bound.