Purification and partial characterization of α1-proteinase inhibitor in the common marmoset (Callithrix jacchus)

Research Highlights
• Marmoset alpha1-proteinase inhibitor was purified from serum using chromatography (immunoaffinity and ceramic hydroxyapatite).
• Partial characterization was performed by reducing gel electrophoresis and enzyme inhibitory assays.
• Protein identity was confirmed with peptide mass fingerprinting and N-terminal amino acid sequencing.
• Purified marmoset α1-PI has characteristics similar to those of α1-PI reported for other species.

Fecal alpha1-proteinase inhibitor (α1-PI) concentration has been to diagnose enteric protein loss in dogs and cats. Chronic lymphocytic enteritis is commonly seen in the marmoset (Callithrix jaccus) and is characterized by hypoalbuminemia. As a prelude to immunoassay development for detecting enteric protein loss, marmoset serum α1-PI was purified using immunoaffinity chromatography and ceramic hydroxyapatite chromatography. Partial characterization was performed by reducing gel electrophoresis and enzyme inhibitory assays. Protein identity was confirmed with peptide mass fingerprinting and N-terminal amino acid sequencing. Molecular mass, relative molecular mass, and isoelectric point for marmoset α1-PI were 54 kDa, 51,677, and 4.8–5.4, respectively. Trypsin, chymotrypsin, and elastase inhibitory activity were observed. N-terminal amino acid sequence for marmoset α1-PI was EDPQGDAAQKMDTSHH. In conclusion, marmoset α1-PI was successfully purified from serum with an overall yield of 12% using a rapid and efficient method. Purified marmoset α1-PI has characteristics similar to those of α1-PI reported for other species.