{"doi":"10.1073/pnas.67.3.1404","title":"Evidence from Chloroplast Fragments for Three Photosynthetic Light Reactions","abstract":"<jats:p>\n                    Previous reports from this laboratory described a new concept of three light reactions in plant photosynthesis comprising two short-wavelength (λ &lt; 700 nm) photoreactions belonging to Photosystem II and one long-wavelength (λ &gt; 700 nm) photoreaction belonging to Photosystem I. Among the electron carriers assigned to Photosystem II were cytochrome\n                    <jats:italic>b</jats:italic>\n                    <jats:sub>559</jats:sub>\n                    and plastocyanin and to Photosystem I, cytochrome\n                    <jats:italic>f</jats:italic>\n                    .\n                  </jats:p>\n                  <jats:p>\n                    According to a widely held view, the light-induced reduction of NADP by water requires the collaboration of Photosystems I and II and involves specifically cytochrome\n                    <jats:italic>f</jats:italic>\n                    and P700 (a portion of chlorophyll\n                    <jats:italic>a</jats:italic>\n                    peculiar to Photosystem I). By contrast, the new concept ascribes the light-induced reduction of NADP by water solely to the two photoreactions of Photosystem II, without the participation of Photosystem I and its components, cytochrome\n                    <jats:italic>f</jats:italic>\n                    and P700.\n                  </jats:p>\n                  <jats:p>\n                    Further evidence in support of the new concept has now been obtained from chloroplast fragments. Two kinds of chloroplast fragments have been prepared: (\n                    <jats:italic>a</jats:italic>\n                    ) one with Photosystem II activity, capable—in the presence of plastocyanin—of photoreducing NADP with water but lacking P700 and functional cytochrome\n                    <jats:italic>f</jats:italic>\n                    and (\n                    <jats:italic>b</jats:italic>\n                    ) another having only Photosystem I activity, lacking plastocyanin, and enriched in P700.\n                  </jats:p>","journal":"Proceedings of the National Academy of Sciences","year":1970,"id":605167,"datarank":0.519860385419959,"base_score":3.4657359027997265,"endowment":3.4657359027997265,"self_citation_contribution":0.519860385419959,"citation_network_contribution":0.0,"self_endowment_contribution":0.519860385419959,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":31,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1553046,"name":"Richard K. Chain","orcid":null,"position":1,"is_corresponding":false},{"id":1553047,"name":"Berah D. McSwain","orcid":null,"position":2,"is_corresponding":false},{"id":1553048,"name":"Harry Y. Tsujimoto","orcid":null,"position":3,"is_corresponding":false},{"id":188806,"name":"David B. Knaff","orcid":null,"position":4,"is_corresponding":false},{"id":78317,"name":"Daniel I. Arnon","orcid":"0000-0001-7998-6316","position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Evidence from Chloroplast Fragments for Three Photosynthetic Light Reactions","abstract":"<jats:p>\n                    Previous reports from this laboratory described a new concept of three light reactions in plant photosynthesis comprising two short-wavelength (λ &lt; 700 nm) photoreactions belonging to Photosystem II and one long-wavelength (λ &gt; 700 nm) photoreaction belonging to Photosystem I. Among the electron carriers assigned to Photosystem II were cytochrome\n                    <jats:italic>b</jats:italic>\n                    <jats:sub>559</jats:sub>\n                    and plastocyanin and to Photosystem I, cytochrome\n                    <jats:italic>f</jats:italic>\n                    .\n                  </jats:p>\n                  <jats:p>\n                    According to a widely held view, the light-induced reduction of NADP by water requires the collaboration of Photosystems I and II and involves specifically cytochrome\n                    <jats:italic>f</jats:italic>\n                    and P700 (a portion of chlorophyll\n                    <jats:italic>a</jats:italic>\n                    peculiar to Photosystem I). By contrast, the new concept ascribes the light-induced reduction of NADP by water solely to the two photoreactions of Photosystem II, without the participation of Photosystem I and its components, cytochrome\n                    <jats:italic>f</jats:italic>\n                    and P700.\n                  </jats:p>\n                  <jats:p>\n                    Further evidence in support of the new concept has now been obtained from chloroplast fragments. Two kinds of chloroplast fragments have been prepared: (\n                    <jats:italic>a</jats:italic>\n                    ) one with Photosystem II activity, capable—in the presence of plastocyanin—of photoreducing NADP with water but lacking P700 and functional cytochrome\n                    <jats:italic>f</jats:italic>\n                    and (\n                    <jats:italic>b</jats:italic>\n                    ) another having only Photosystem I activity, lacking plastocyanin, and enriched in P700.\n                  </jats:p>","is_dataset_classified":null,"base_score":3.4657359027997265,"endowment":3.4657359027997265,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"16591881","pmcid":"PMC283366","openalex_id":"https://openalex.org/W1979468667","authors":[],"funders":[],"total_grants":0,"fwci":4.7614,"citation_percentile":0.94513907,"influential_citations":0,"citation_trend":[],"oa_status":"green","license":null,"oa_locations":[{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/283366","host_type":"repository"},{"url":"https://www.ncbi.nlm.nih.gov/pmc/articles/283366","host_type":"repository"},{"url":"https://pnas.org/doi/pdf/10.1073/pnas.67.3.1404","host_type":"publisher"},{"url":"https://doi.org/10.1073/pnas.67.3.1404","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/16591881","host_type":"repository"}],"fields_of_study":["Photosynthetic Processes and Mechanisms","Light effects on plants","Photoreceptor and optogenetics research"],"mesh_terms":[],"keywords":["P700","Plastocyanin","Photosystem I","Cytochrome b6f complex","Photosystem II","Photosystem","Photochemistry","Photosynthetic reaction centre","Light-harvesting complexes of green plants","Chloroplast","Photosynthesis","Chemistry","Cytochrome","Biochemistry","Electron transfer"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Clean water and sanitation"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-07-30T01:48:30.992530Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}