Limited proteolysis of the alpha-macroglobulin rat alpha 1-inhibitor-3. Implications for a domain structure.
Rat alpha 1-inhibitor-3 is a 180-kDa monomeric proteinase inhibitor found in high concentration in rat plasma. By several criteria it has been shown to be a member of the family of alpha-macroglobulin proteinase inhibitors often exemplified by the tetrameric human alpha 2-macroglobulin. We have used limited proteolysis of rat alpha 1-inhibitor-3 to probe the domain structure of this family of proteins. Proteinases of different specificities, including trypsin, chymotrypsin, thermolysin, and Staphylococcus aureus V8 proteinase, were employed and a common fragmentation pattern was observed when the reaction products were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These fragments were electrotransferred to polyvinylidene difluoride membranes and subjected to NH2-terminal amino acid sequence analysis in order to position them within the context of the primary structure. The fragmentation pattern may define the domain structure of alpha 1-inhibitor-3 and serve as a model for the domain organization of the family of alpha-macroglobulin proteinase inhibitors.
Rubenstein
D S
DS
Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710.
Enghild
J J
JJ
Pizzo
S V
SV
D000209:Acute-Phase Proteins; D000595:Amino Acid Sequence; D000818:Animals; D002918:Chymotrypsin / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010206:Papain / Q000378:metabolism; D010446:Peptide Fragments / Q000302:isolation & purification; D010449:Peptide Mapping; D011480:Protease Inhibitors / Q000737:chemistry*; D051381:Rats; D013820:Thermolysin / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000737:chemistry*
D000209:Acute-Phase Proteins; D010446:Peptide Fragments; D011480:Protease Inhibitors; C017894:alpha 1-inhibitor 3; D000511:alpha-Macroglobulins; D002918:Chymotrypsin; D014357:Trypsin; D010206:Papain; D013820:Thermolysin