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.