Purification and characterization of alpha 2-macroglobulin from the white shrimp (Penaeus vannamei).
alpha(2)-Macroglobulin (alpha(2)M) is a broad-spectrum protease-binding protein abundant in plasma from vertebrates and several invertebrate phyla. This protein was purified from cell-free hemolymph of the white shrimp, Penaeus vannamei, using Blue-Sepharose and Phenyl-Sepharose chromatography. The shrimp alpha(2)M is a 380 kDa protein, a homodimer of two apparently identical subunits of approximately 180 kDa linked by disulphide bridges. The amino acid sequence of the N-terminus is similar to the Limulus alpha(2)M counterpart. The shrimp alpha(2)M has a wide inhibition spectrum against different proteinase types including trypsin, leucine amino peptidase, chymotrypsin, elastase and papain. The secondary structure of shrimp alpha(2)M is mainly beta-sheet (36%), with a characteristic minimum elipticity at 217 nm. Evidence for a thiolester-mediated inhibition mechanism of proteases by alpha(2)M was provided by inactivation with methylamine.
Gollas-Galván
Teresa
T
Marine Biotechnology, CIAD, P.O. Box 1735, Hermosillo, Son. 83000, Mexico.
Sotelo-Mundo
Rogerio R
RR
Yepiz-Plascencia
Gloria
G
Vargas-Requena
Claudia
C
Vargas-Albores
Francisco
F
D000595:Amino Acid Sequence; D000818:Animals; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000737:chemistry* / Q000235:genetics; D000511:alpha-Macroglobulins / Q000032:analysis / Q000302:isolation & purification*
D000511:alpha-Macroglobulins