Haeme binding to human serum albumin and to the three large cyanogen bromide albumin fragments

Hrkal, Zbyněk; Kodı́ček, Milan; Vodrážka, Z.; Meloun, B.; Morávek, L.

doi:10.1016/0020-711x(78)90110-6

Cited by 27 publications

(13 citation statements)

References 24 publications

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“…HSA possesses a single high-affinity binding site for heme [40,41] near the hydrophobic cavity of subdomain IIA [42,43]. The heme-HSA adduct has a characteristic Soret absorption at 405 nm with an intensity that depends on the amount of heme bound to the protein, which can be modified by drugs capable of competing for that site.…”

Section: Resultsmentioning

confidence: 99%

Interactions of arene–Ru(II)–chloroquine complexes of known antimalarial and antitumor activity with human serum albumin (HSA) and transferrin

Martínez

Suárez

Shand

et al. 2011

Journal of Inorganic Biochemistry

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The interactions of π-arene-Ru(II)-chloroquine complexes with human serum albumin (HSA), apotransferrin and holotransferrin have been studied by circular dichroism (CD) and UV-Visible spectroscopies, together with isothermal titration calorimetry (ITC). The data for [Ru(η6-p-cymene)(CQ)(H2O)Cl]PF6 (1), [Ru(η6-benzene)(CQ)(H2O)Cl]PF6 (2), [Ru(η6-p-cymene)(CQ)(H2O)2][PF6]2 (3), [Ru(η6-p-cymene)(CQ)(en)][PF6]2 (4), [Ru(η6-p-cymene)(η6-CQDP)][BF4]2 (5) (CQ: chloroquine; DP: diphosphate; en: ethylenediamine), in comparison with CQDP and [Ru(η6-p-cymene)(en)Cl][PF6] (6) as controls demonstrate that 1, 2, 3, and 5, which contain exchangeable ligands, bind to HSA and to apotransferrin in a covalent manner. The interaction did not affect the α-helical content in apotransferrin but resulted in a loss of this type of structure in HSA. The binding was reversed in both cases by a decrease in pH and in the case of the Ru-HSA adducts, also by addition of chelating agents. A weaker interaction between complexes 4 and 6 and HSA was measured by ITC but was not detectable spectroscopically. No interactions were observed for complexes 4 and 6 with apotransferrin or for CQDP with either protein. The combined results suggest that the arene-Ru(II)-chloroquine complexes, known to be active against resistant malaria and several lines of cancer cells, also display a good transport behavior that makes them good candidates for drug development.

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Section: Resultsmentioning

confidence: 99%

Interactions of arene–Ru(II)–chloroquine complexes of known antimalarial and antitumor activity with human serum albumin (HSA) and transferrin

Martínez

Suárez

Shand

et al. 2011

Journal of Inorganic Biochemistry

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“…Hrkal et al (18) suggested that the primary binding site for hemin is located in the amino acid sequence 124-298 of HSA, in agreement with the observation that hemin binds close to the middle of the albumin It has been shown that hemin binds to human serum albumin (HSA), which has a structure similar to BSA, with a high association constant, 5.0 x 10 7 M -1 at 23ºC, pH 7.5 (6,9). Based on the magnitude of the binding constants and results of kinetic studies, Hrkal et al (18) suggested that this primary binding site is located in the 124-298 amino acid sequence of HSA.…”

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confidence: 99%

“…Based on the magnitude of the binding constants and results of kinetic studies, Hrkal et al (18) suggested that this primary binding site is located in the 124-298 amino acid sequence of HSA. They proposed that the presence of the C-terminal part of albumin was essential for the spatial configuration of the site.…”

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confidence: 99%

“…According to these data and on the basis of the non-linearity of the BSA SternVolmer plot (Figure 1), we suggest that the primary binding site for hemin in BSA is located asymmetrically between the two tryptophans along the sequence formed by subdomains IB and IIA, closer to the tryptophan residue 212. Experiments with HSA fragments revealed that different peptides in amino acid sequence 124-298 were able to bind hemin with relatively high affinity (18). The gradual loss of linearity of the Stern-Volmer plots with continuous addition of hemin (Figure 1) suggests that the secondary sites for hemin are located near tryptophan residue(s).…”

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confidence: 99%

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Quenching of the intrinsic fluorescence of bovine serum albumin by chlorpromazine and hemin

Silva

Cortez

Louro

2004

Braz J Med Biol Res

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The binding of chlorpromazine (CPZ) and hemin to bovine serum albumin was studied by the fluorescence quenching technique. CPZ is a widely used anti-psychotic drug that interacts with blood components, influences bioavailability, and affects function of several biomolecules. Hemin is an important ferric residue of hemoglobin that binds within the hydrophobic region of albumin with high specificity. Quenching of the intrinsic fluorescence of bovine serum albumin (BSA) was observed by selectively exciting tryptophan residues at 290 nm. Emission spectra were recorded in the range from 300 to 450 nm for each quencher addition. Stern-Volmer graphs were plotted, and the quenching constant estimated for BSA solution titrated with hemin at 25ºC was 1.44 (± 0.05) x 10 5 M -1 . Results showed that bovine albumin tryptophans are not equally accessible to CPZ, in agreement with the idea that polar or charged quenchers have more affinity for amino acid residues on the outer wall of the protein. Hemin added to albumin solution at a molar ratio of 1:1 quenched about 25% of their fluorescence. The quenching effect of CPZ on albumin-hemin solution was stronger than on pure BSA. This increase can be the result of combined conformational changes in the structure of albumin caused firstly by hemin and then by CPZ. Our results suggest that the primary binding site for hemin on bovine albumin may be located asymmetrically between the two tryptophans along the sequence formed by subdomains IB and IIA, closer to tryptophan residue 212.

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“…Albumin, a major component in gingival crevicular fluid from both healthy and inflamed periodontal sites (26), is a potential source of peptides and amino acids for sub-and supragingival plaque microorganisms and in vitro can serve as sole carbon and nitrogen source for Porphyromonas gingivalis (30). In plasma, albumin binds and transports many important biological ligands including heme (iron protoporphyrin IX) for which it has a high affinity (1,2,17,19,24). Hemalbumin formation is an important sequestration phenomenon both for heme transport and for the reduction of its microbial availability.…”

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Albumin and hemalbumin degradation by Porphyromonas gingivalis

Smalley

Birss

1997

Oral Microbiology and Immunology

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Degradation of bovine albumin and hemalbumin by Porphyromonas gingivalis W50 cells under non-reducing conditions at 37 degrees C was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and densitometry. Albumin and hemalbumins with heme:protein molar ratios of 1:1, 4:1 and 8:1 were degraded, yielding protease-resistant 55.6-kDa peptides. Cells of strains WPH 35, 11834 and Bg 381 also produced a similar digestion pattern. N-terminal sequencing of the 55.6-kDa albumin digestion fragment revealed two peptides with the sequences 82glu-thr-tyr-gly-asp-met-ala and 95gln-pro-glu-arg-asn-glu-cys, indicating cleavage in the N-terminal hinge region. Tosyllysylchloromethylketone and N-ethylmaleimide were the most effective in inhibiting breakdown of albumin and hemalbumin with a 1:1 heme:protein ratio. Initial degradation rates of albumin and all hemalbumins were similar, but the total amount of hemalbumins degraded over 7.5 h decreased with increased ratio of bound hemin. The specific proteolysis of hemalbumin may enable P. gingivalis to release hemin from a region of the molecule where heme binding is least avid.

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Haeme binding to human serum albumin and to the three large cyanogen bromide albumin fragments

Cited by 27 publications

References 24 publications

Interactions of arene–Ru(II)–chloroquine complexes of known antimalarial and antitumor activity with human serum albumin (HSA) and transferrin

Interactions of arene–Ru(II)–chloroquine complexes of known antimalarial and antitumor activity with human serum albumin (HSA) and transferrin

Quenching of the intrinsic fluorescence of bovine serum albumin by chlorpromazine and hemin

Albumin and hemalbumin degradation by Porphyromonas gingivalis

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