PURIFICATION AND CHARACTERIZATION OF PIG INTER-ALPHA-INHIBITOR AND ITS CONSTITUTIVE HEAVY-CHAINS

With the view of investigating the metabolism of inter-alpha-inhibitor , a plasma serine-proteinase inhibitor, in an animal model of inflamma tory syndrome, we isolated inter-alpha-inhibitor from pig plasma. A hi gh yield was obtained (140 mg/liter) with a two-step procedure: anion- exchange chromatography followed by affinity chromatography on heparin -Sepharose. In contrast to bovine inter-alpha-inhibitor, pig inter-alp ha-inhibitor was highly similar to human inter-ct-inhibitor: its heavy chains are homologous to the human H1 and H2 heavy chains, as shown b y chromatographic and electrophoretic properties, cross-immunoreactivi ty and N-terminal sequencing. Pig may therefore represent a good anima l model to study inter-alpha-inhibitor metabolism and elucidate its ph ysiological role.