10.1073\/pnas.85.17.6571<\/a><\/p>\nAuthors:<\/h4>\n
Jack H. Kaplan, Graham C. R. Ellis\u2010Davies<\/p>\n
Abstract:<\/h4>\n
The properties of a recently synthesized photolabile chelator for divalent cations are described, the affinity of which for Ca2+ changes by some 5 orders of magnitude on illumination. The compound 1-(2-nitro-4,5-dimethoxyphenyl)-N,N,N’,N’-tetrakis[(oxycarbonyl)me thyl]-1,2-ethanediamine (DM-nitrophen) binds Ca2+ (Kd approximately 5.0 x 10(-9) M) and Mg2+ (Kd approximately 2.5 x 10(-6) M) with relatively high affinities. On exposure of the DM-nitrophen-Ca2+ complex to UV light in the 350-nm range, the chelator is cleaved yielding iminodiacetic products with a much lower affinity for Ca (Kd approximately 3 x 10(-3) M) and the free [Ca2+] increases. The quantum yield for Ca2+ release is 0.18. In experiments with chemically skinned skeletal muscle fibers, a fully relaxed fiber equilibrated with DM-nitrophen-Ca2+ complex produced maximal contraction after a single flash from a frequency-doubled ruby laser (347 nm). Half-maximal tension was achieved in approximately 40 ms, some 5 times faster than that obtained after a rapid solution change from a Ca2+-free to a Ca2+-containing solution. In experiments with resealed human erythrocyte ghosts, irradiation of ghosts containing the DM-nitrophen-Ca2+ complex activates a Ca2+-dependent K+ efflux pathway, which is not observed in the absence of illumination. DM-nitrophen is sufficiently stable and photolabile to be used as a caged Ca (or caged Mg) for the rapid photoinitiation of divalent cation-dependent processes over a wide concentration range with a significant increase in temporal resolution over conventional mixing methods.<\/p>\n","protected":false},"excerpt":{"rendered":"
DOI: 10.1073\/pnas.85.17.6571 Authors: Jack H. Kaplan, Graham C. R. Ellis\u2010Davies Abstract: The properties of a recently synthesized photolabile chelator for divalent cations are described, the affinity of which for Ca2+ changes by some 5 orders of magnitude on illumination. The compound 1-(2-nitro-4,5-dimethoxyphenyl)-N,N,N’,N’-tetrakis[(oxycarbonyl)me thyl]-1,2-ethanediamine (DM-nitrophen) binds Ca2+ (Kd approximately 5.0 x 10(-9) M) and Mg2+ (Kd […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21],"tags":[],"class_list":["post-805","post","type-post","status-publish","format-standard","hentry","category-rsc-200"],"_links":{"self":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/posts\/805","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=805"}],"version-history":[{"count":0,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=\/wp\/v2\/posts\/805\/revisions"}],"wp:attachment":[{"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=805"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=805"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/citations.tools.bio-logic.fr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=805"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}