Identification and partial characterization of alpha 2-macroglobulin from the tuatara (Sphenodon punctatus).
alpha 2-Macroglobulin (alpha 2-M), a large molecular mass proteinase-binding protein, was identified in plasma from tuatara (Sphenodon), a rare reptile endemic to New Zealand. In this genus, alpha 2-M constitutes 11-13% of total plasma protein (approximately 2.2-3.9 mg/mL). Analysis of blood samples collected at approximately monthly intervals from individual tuatara indicated that the plasma level of alpha 2-M remains fairly constant. The subunits of tuatara alpha 2-M have an apparent molecular mass of approximately 160 kDa as determined by SDS-polyacrylamide gel electrophoresis and the intact protein is an oligomer that contains inter-chain disulfide bonds. N-terminal sequence analyses of tuatara alpha 2-M revealed a distinct similarity to alpha-macroglobulins of other vertebrates and that at least two types of alpha 2-M subunits are present in plasma of tuatara.
Brown
M A
MA
Biochemistry and Genetics Research Unit, School of Biological Sciences, Victoria University of Wellington, New Zealand. mabrown@unixg.ubc.ca
Carne
A
A
Chambers
G K
GK
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D010450:Endopeptidases / Q000097:blood; D008116:Lizards / Q000097:blood*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D000511:alpha-Macroglobulins / Q000032:analysis*
D000596:Amino Acids; D000511:alpha-Macroglobulins; D010450:Endopeptidases