{"id":4791,"date":"2023-02-17T07:10:05","date_gmt":"2023-02-17T07:10:05","guid":{"rendered":"http:\/\/ionchanneltargets.com\/resource_library\/herg-pharmacology-of-herg-recorded-on-nanions-port-a-patch\/"},"modified":"2023-02-17T07:10:06","modified_gmt":"2023-02-17T07:10:06","slug":"2010-delineating-electrogenic-reactions-during-lactose-h-symport","status":"publish","type":"resource_library","link":"https:\/\/nanion.com\/zh-hans\/resource_library\/2010-delineating-electrogenic-reactions-during-lactose-h-symport\/","title":{"rendered":"2010 &#8211; Delineating electrogenic reactions during lactose\/H+ symport"},"content":{"rendered":"<p>Electrogenic reactions accompanying downhill lactose\/H+\u00a0symport catalyzed by the lactose permease of Escherichia coli (LacY) have been assessed using solid-supported membrane-based electrophysiology with improved time resolution. Rates of charge translocation generated by purified LacY reconstituted into proteoliposomes were analyzed over a pH range from 5.2 to 8.5, which allows characterization of two electrogenic steps in the transport mechanism: (i) a weak electrogenic reaction triggered by sugar binding and observed under conditions where H+\u00a0translocation is abolished either by acidic pH or by a Glu325 \u2192 Ala mutation in the H+\u00a0binding site (this step with a rate constant of \u223c200 s\u22121\u00a0for wild-type LacY leads to an intermediate proposed to represent an \u201coccluded\u201d state) and (ii) a major electrogenic reaction corresponding to 94% of the total charge translocated at pH 8, which is pH-dependent with a maximum rate of \u223c30 s\u22121\u00a0and a pK of 7.5. This partial reaction is assigned to rate-limiting H+\u00a0release on the cytoplasmic side of LacY during turnover. These findings together with previous electrophysiological results and biochemical\u2212biophysical studies are included in an overall kinetic mechanism that allows delineation of the electrogenic steps in the reaction pathway.<\/p>\n","protected":false},"featured_media":0,"template":"","products_tags":[36],"resource_type":[75],"application_areas":[108],"therapeutic_areas":[],"target_categories":[60],"target_families":[375],"targets":[],"resource_keyword":[],"class_list":["post-4791","resource_library","type-resource_library","status-publish","hentry","products_tags-surfe2r-n1","resource_type-publication","application_areas-transporters","target_categories-transporters","target_families-symporter"],"acf":[],"_links":{"self":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_library\/4791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_library"}],"about":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/types\/resource_library"}],"wp:attachment":[{"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/media?parent=4791"}],"wp:term":[{"taxonomy":"products_tags","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/products_tags?post=4791"},{"taxonomy":"resource_type","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_type?post=4791"},{"taxonomy":"application_areas","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/application_areas?post=4791"},{"taxonomy":"therapeutic_areas","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/therapeutic_areas?post=4791"},{"taxonomy":"target_categories","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/target_categories?post=4791"},{"taxonomy":"target_families","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/target_families?post=4791"},{"taxonomy":"targets","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/targets?post=4791"},{"taxonomy":"resource_keyword","embeddable":true,"href":"https:\/\/nanion.com\/zh-hans\/wp-json\/wp\/v2\/resource_keyword?post=4791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}