title: Molecular properties of the slow inward calcium channel. Molecular weight determinations by radiation inactivation and covalent affinity labeling.
abstract: The slow inward calcium channel, identified by physiologic and pharmacologic responses and [3H]nitrendipine-specific binding, has been characterized by radiation inactivation and covalent affinity labeling. Target size analysis of guinea pig ileum longitudinal smooth muscle membranes indicates a molecular weight of 278,000 for the calcium channel. An affinity label analog of nifedipine and nitrendipine, 2,6-dimethyl-3,5-dicarbomethoxy-4-(2-isothiocyanatophenyl)-1,4-dihydropyridine, was found to inhibit the calcium channel by a covalent interaction with a protein subunit (Mr = 45,000) of the calcium channel.
mesh_terms: D000345:Affinity Labels / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004095:Dihydropyridines; D006168:Guinea Pigs; D007473:Ion Channels / Q000378:metabolism* / Q000528:radiation effects; D008722:Methods; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D009543:Nifedipine / Q000031:analogs & derivatives / Q000378:metabolism; D009568:Nitrendipine; D011725:Pyridines / Q000378:metabolism
chemical_list: D000345:Affinity Labels; D004095:Dihydropyridines; D007473:Ion Channels; D011725:Pyridines; C038806:1,4-dihydropyridine; D009568:Nitrendipine; D009543:Nifedipine; D002118:Calcium