TY - JOUR
T1 - The latent form of macropain (high molecular weight multicatalytic protease) restores ATP-dependent proteolysis to soluble extracts of BHK fibroblasts pretreated with anti-macropain antibodies
AU - McGuire, Michael J.
AU - DeMartino, George N.
N1 - Funding Information:
This work was supported (DK 29829). We thank Elizabeth by a grant from the National Institutes Wisakowsky for typing the manuscript.
PY - 1989/4/28
Y1 - 1989/4/28
N2 - Specific immunoadsorption of the high molecular weight multicatalytic protease, macropain, from postmicrosomal extracts of BHK fibroblasts inhibited ATP-dependent proteolysis of exogenous protein substrates. The immunoprecipitated macropain represented the latent (L) form of the protease because it had low protease activity but was activated by methods that activate purified macropain L. Reconstitution of the antibody-treated extracts with purified macropain L, but not macropain A, from bovine heart or human erythrocytes, completely restored ATP-dependent proteolysis, even though ATP did not directly activate either purified macropain L or the immunoprecipitated protease. Reconstituted ATP-dependent proteolysis was saturable with respect to added macropain and never exceeded the level of proteolysis present in the original extract. These results indicate that macropain L plays a key role in ATP-dependent proteolysis but suggest that the protease may require interaction with or modification by another cellular component to demonstrate this effect.
AB - Specific immunoadsorption of the high molecular weight multicatalytic protease, macropain, from postmicrosomal extracts of BHK fibroblasts inhibited ATP-dependent proteolysis of exogenous protein substrates. The immunoprecipitated macropain represented the latent (L) form of the protease because it had low protease activity but was activated by methods that activate purified macropain L. Reconstitution of the antibody-treated extracts with purified macropain L, but not macropain A, from bovine heart or human erythrocytes, completely restored ATP-dependent proteolysis, even though ATP did not directly activate either purified macropain L or the immunoprecipitated protease. Reconstituted ATP-dependent proteolysis was saturable with respect to added macropain and never exceeded the level of proteolysis present in the original extract. These results indicate that macropain L plays a key role in ATP-dependent proteolysis but suggest that the protease may require interaction with or modification by another cellular component to demonstrate this effect.
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U2 - 10.1016/0006-291X(89)92521-7
DO - 10.1016/0006-291X(89)92521-7
M3 - Article
C2 - 2719706
AN - SCOPUS:0024980075
SN - 0006-291X
VL - 160
SP - 911
EP - 916
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -