Protease inhibitor homologues of dendrotoxin do not bind to dendrotoxin acceptors on synaptosomal membranes or facilitate neuromuscular transmission.
The dendrotoxins are a homologous group of potassium channel-blocking polypeptides found in mamba snake venom. They are similar in sequence and structure to Kunitz-type serine protease inhibitors. Modified and native protease inhibitors were assayed for dendrotoxin-like activity using radioligand-binding and twitch tension-recording methods. Despite the large number and high concentration of compounds tested, no protease inhibitor displayed dendrotoxin-like activity. The results indicate that the protease-inhibiting and potassium channel-blocking activities of these two groups of polypeptides are not linked.
Marshall
D L
DL
Department of Physiology and Pharmacology, Strathclyde University, Glasgow, Scotland.
Harvey
A L
AL
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D004546:Elapid Venoms / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D015221:Potassium Channels; D011480:Protease Inhibitors / Q000378:metabolism* / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D011950:Receptors, Cholinergic / Q000378:metabolism*; D013329:Structure-Activity Relationship; D009435:Synaptic Transmission / Q000187:drug effects*; D013574:Synaptosomes / Q000378:metabolism* / Q000648:ultrastructure
D004546:Elapid Venoms; D007457:Iodine Radioisotopes; D015221:Potassium Channels; D011480:Protease Inhibitors; D011950:Receptors, Cholinergic; C042467:dendrotoxin receptor; C020273:dendrotoxin