Primary structure of a protease isoinhibitor from bovine spleen. A possible intermediate in the processing of the primary gene product.
Sequence studies on the protease isoinhibitor I isolated from bovine spleen have revealed that it consists of two molecular variants which differ only in the presence of an additional COOH-terminal residue, asparagine, in the less abundant form. The complete amino acid sequence shows that they are composed of 65 or 66 residues and predicts Mr of 7223 or 7338, respectively. The sequences correspond exactly to the 58-residue polypeptide chain of spleen isoinhibitor II plus NH2- and COOH-terminal extensions of 2 and 5 or 6 amino acid residues, respectively. Moreover the entire sequences are located within the 100-residue structure deduced from the mRNA and DNA sequences of the putative precursor. These data support the idea that the molecular variants of isoinhibitor I are either mature proteins with distinct functional roles, or intermediates in the multistage processing of the primary product of gene expression, which eventually leads to the mature protein, i.e. inhibitor II.
Barra
D
D
Dipartimento di Scienze Biochimiche, Università di Roma La Sapienza, Italy.
Simmaco
M
M
Bossa
F
F
Fioretti
E
E
Angeletti
M
M
Ascoli
F
F
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D005796:Genes; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D011480:Protease Inhibitors / Q000235:genetics* / Q000302:isolation & purification; D011506:Proteins; D012333:RNA, Messenger / Q000235:genetics; D013154:Spleen / Q000378:metabolism*
D010446:Peptide Fragments; D011480:Protease Inhibitors; D011506:Proteins; D012333:RNA, Messenger