| Summary: | 碩士 === 台北醫學院 === 醫學研究所 === 85 === The alpha 2 Macroglobulin (A2M) are classified as broad-
spectrum inhibitorsbecause of their ability to entrap protease
of different specificites and cata-lytic class. In the previous
studies from our laboratory, the putative frog A2McDNA
containing thioester region sequences has been cloned. In this
report, theA2M-like protease inhibitor from plasma of the Rana
trigrina was purified to a-pparent homogeneity by DEAE-sepharose
CL-6B anion-exchange column and preparat-ive electrophoresis.
The purified protein resembled verterbrate A2Ms in that
itdisplays a broad specificity and inhibited the activity of
trypsin, chymotryps-in, papain, pepsin and elastase. Sensitivity
of this purified protein to methy-lamine and autolytic cleavage
suggested the presence of an internal bata-cyste-inyl-r-glutamyl
thioester. The purified protein was tetramer of 180KDa and had
and apparent mass of approximately 720Kda when examined by non-
reducing and re-ducing sodium dodecylsulfate-polyacrylamide gel
(SDS-PAGE), and gel filteration. When boiled in SDS it under
went autolytic fragmentation to produce two bandsof
approximately 110 and 80KDa resemble to human A2M. The amino
acid compositi-on showed similarities with the well-
characterized vertebrate A2Ms. These resu-lts suggested the
purified protein was an A2M-like protease inhibitor.
|
|---|
