Studies on Limzdus Amoebocyte Lysate
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چکیده
A pro-clotting enzyme capable of causing the gelation of clottable proteins in Limulw polgphemus (horseshoe crab) has been purified to apparent homogeneity as judged by sodium dodecyl sulfate-gel electrophoresis. The activation of the pro-clotting enzyme depended on the presence of both Ca’+ and endotoxin. It contained y-carboxyglutamic acids and gave a single NlI,-terminal lysine. The enzyme was inhibited by diisopropyl fluorophosphate, phenylmethylsulfonyl fluoride, and soy bean trypsin inhibitor, indicating that it is a serine protease. The molecular weight of the proclotting enzyme was determined to be at least l.iO,OOO by sodium dodecyl sulfate-gel electrophoresis under reducing and denaturing conditions. The protein appears to consist of a single peptide chain, since exposure of the reduced and carboxymethylated enzyme to 6 H guanidine hydrochloride failed to dissociate it into any subunits.
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