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The most basic phospholipase A2 (PLA2), VRV-PL-VIIIa, was purified from (Sri Lankan) Vipera russelli venom. It is a major component of the venom, contributing over 40% to the whole venom PLA2 activity. The purity of VRV-PL-VIIIa was ascertained by electrophoresis and by reverse phase high-pressure liquid-chromatography (RP-HPLC). VRV-PL-VIIIa had an(More)
Botulinum neurotoxins (BoNT) are zinc metalloproteases that cleave and inactivate cellular proteins essential for neurotransmitter release. Because the paralytic effect of BoNT is a consequence of its enzymatic activity, selective inhibitors may be useful as drugs or as tools for further research. To expedite inhibitor discovery, we developed(More)
Type A botulinum neurotoxin, a zinc-dependent endoproteinase that selectively cleaves the neuronal protein SNAP-25, can also cleave relatively short peptides. We found that bovine and other serum albumins stimulated the type A-catalyzed hydrolysis of synthetic peptide substrates, through a direct effect on the kinetic constants of the reaction. Furthermore,(More)
Neonatal mice resist the lethal effect of Waglerin-1. Because Waglerin-1 blocks the nicotinic acetylcholine receptor of mature end-plates, the appearance of lethality may result from the epsilon- for gamma-subunit substitution. In support of this hypothesis, adult knockout (KO) mice lacking the gene coding for the epsilon-subunit resist the lethal effect of(More)
The peptide N-acetyl-CRATKML-amide is an effective inhibitor of type A botulinum neurotoxin (BoNT A) protease activity [Schmidt et al., FEBS Lett. 435 (1998) 61-64]. To improve inhibitor binding, the peptide was modified by replacing cysteine with other sulfhydryl-containing compounds. Ten peptides were synthesized. One peptide adapted the structure of(More)
Type A botulinum neurotoxin (botox A) is a zinc metalloprotease that cleaves only one peptide bond in the synaptosomal protein, SNAP-25. Single-residue changes in a 17-residue substrate peptide were used to develop the first specific, competitive inhibitors of its proteolytic activity. Substrate analog peptides with P4, P3, P2' or P3' cysteine were readily(More)
The ultimate molecular action of botulinum neurotoxin (BoNT) is a Zn-dependent endoproteolytic activity on one of the three SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins. There are seven serotypes (A-G) of BoNT having distinct cleavage sites on the SNARE substrates. The proteolytic activity is located on the(More)
The virulent spore-forming bacterium Bacillus anthracis secretes anthrax toxin composed of protective antigen (PA), lethal factor (LF) and edema factor (EF). LF is a Zn-dependent metalloprotease that inactivates key signaling molecules, such as mitogen-activated protein kinase kinases (MAPKK), to ultimately cause cell death. We report here the(More)
Clostridium botulinum type E neurotoxin, a single-chain protein of Mr 147,000, was purified and subjected to amino acid sequencing. The same was done for single-chain botulinum type B neurotoxin (Mr 152,000), and for the heavy and light chains (Mr 104,000 and 51,000 respectively) derived from type B by limited trypsin digestion. Twelve to eighteen residues(More)