Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX
The study of the interaction of synthetic protoporphyrin IX (PpIXs) and protoporphyrin IX extracted from Harderian glands of ssp Rattus novergicus albinus rats (PpIXe) with bovine serum albumin (BSA) was conducted in water at pH 7.3 and pH 4.5 by optical absorption and fluorescence spectroscopies. P...
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| Formato: | Artigo |
| Idioma: | English |
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Associação Brasileira de Divulgação Científica
2022-10-01
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| Colecção: | Brazilian Journal of Medical and Biological Research |
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| Acesso em linha: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2022000100662&lng=en&tlng=en |
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| author | D.C.K. Codognato F.S. Pena E.R. dos Reis A.P. Ramos I.E. Borissevitch |
| author_facet | D.C.K. Codognato F.S. Pena E.R. dos Reis A.P. Ramos I.E. Borissevitch |
| author_sort | D.C.K. Codognato |
| collection | DOAJ |
| description | The study of the interaction of synthetic protoporphyrin IX (PpIXs) and protoporphyrin IX extracted from Harderian glands of ssp Rattus novergicus albinus rats (PpIXe) with bovine serum albumin (BSA) was conducted in water at pH 7.3 and pH 4.5 by optical absorption and fluorescence spectroscopies. PpIXs is present as H- and J-aggregates in equilibrium with themselves and with monomers. The PpIXs charge is 2− at pH 7.3 and 1− at pH 4.5. This increases its aggregation at pH 4.5 and shifts the equilibrium in favor of J-aggregates. In spite of electrostatic attraction at pH 4.5, where BSA is positive, the binding constant (Kb) of PpIXs to BSA is 20% less than that at pH 7.3, where BSA is negative. This occurs because higher aggregation of PpIXs at pH 4.5 reduces the observed Kb value. At both pHs, water-soluble PpIXe exists in the monomeric form with the charge of 1− and its Kb exceeds that of PpIXs. At pH 4.5, its Kb is 12 times higher than that at pH 7.3 due to electrostatic attraction between the positively charged BSA and the negatively charged PpIXe. The higher probability of PpIXe binding to BSA makes PpIXe more promising as a fluorescence probe for fluorescence diagnostics and as a photosensitizer for photodynamic therapy. The existence of PpIXe in the monomeric form can explain its faster cell internalization. Aggregation reduces quantum yields and lifetimes of the PpIXs excited states, which explains higher phototoxicity of PpIXe toward malignant cells compared with PpIXs. |
| first_indexed | 2024-04-13T22:55:50Z |
| format | Article |
| id | doaj.art-715dac78e9a94e6fbd7e8bb82bd02e5d |
| institution | Directory Open Access Journal |
| issn | 1414-431X |
| language | English |
| last_indexed | 2024-04-13T22:55:50Z |
| publishDate | 2022-10-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-715dac78e9a94e6fbd7e8bb82bd02e5d2022-12-22T02:26:00ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research1414-431X2022-10-015510.1590/1414-431x2022e12272Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IXD.C.K. Codognatohttps://orcid.org/0000-0002-8622-275XF.S. Penahttps://orcid.org/0000-0001-5951-2949E.R. dos Reishttps://orcid.org/0000-0002-9093-2025A.P. Ramoshttps://orcid.org/0000-0001-6200-8989I.E. Borissevitchhttps://orcid.org/0000-0003-2448-2625The study of the interaction of synthetic protoporphyrin IX (PpIXs) and protoporphyrin IX extracted from Harderian glands of ssp Rattus novergicus albinus rats (PpIXe) with bovine serum albumin (BSA) was conducted in water at pH 7.3 and pH 4.5 by optical absorption and fluorescence spectroscopies. PpIXs is present as H- and J-aggregates in equilibrium with themselves and with monomers. The PpIXs charge is 2− at pH 7.3 and 1− at pH 4.5. This increases its aggregation at pH 4.5 and shifts the equilibrium in favor of J-aggregates. In spite of electrostatic attraction at pH 4.5, where BSA is positive, the binding constant (Kb) of PpIXs to BSA is 20% less than that at pH 7.3, where BSA is negative. This occurs because higher aggregation of PpIXs at pH 4.5 reduces the observed Kb value. At both pHs, water-soluble PpIXe exists in the monomeric form with the charge of 1− and its Kb exceeds that of PpIXs. At pH 4.5, its Kb is 12 times higher than that at pH 7.3 due to electrostatic attraction between the positively charged BSA and the negatively charged PpIXe. The higher probability of PpIXe binding to BSA makes PpIXe more promising as a fluorescence probe for fluorescence diagnostics and as a photosensitizer for photodynamic therapy. The existence of PpIXe in the monomeric form can explain its faster cell internalization. Aggregation reduces quantum yields and lifetimes of the PpIXs excited states, which explains higher phototoxicity of PpIXe toward malignant cells compared with PpIXs.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2022000100662&lng=en&tlng=enSynthetic and endogenous protoporphyrin IXAggregationBovine serum albuminBindingpH effects |
| spellingShingle | D.C.K. Codognato F.S. Pena E.R. dos Reis A.P. Ramos I.E. Borissevitch Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX Brazilian Journal of Medical and Biological Research Synthetic and endogenous protoporphyrin IX Aggregation Bovine serum albumin Binding pH effects |
| title | Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX |
| title_full | Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX |
| title_fullStr | Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX |
| title_full_unstemmed | Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX |
| title_short | Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX |
| title_sort | effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin ix |
| topic | Synthetic and endogenous protoporphyrin IX Aggregation Bovine serum albumin Binding pH effects |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2022000100662&lng=en&tlng=en |
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