A study of the reaction of protoporphyrin IX with human globin

Abstract

The present paper reports an investigation of the reaction of protoporphyrin IX with globin prepared from the HbA(0) component of human blood. The porphyringlobin produced is always heterogeneous; however, when globin is used immediately after preparation, its affinity for porphyrin is higher and the product less heterogeneous than when the globin has been frozen or freeze-dried. The affinity of globin for haemin is less affected by its history. With freshly prepared globin, reconstitution at room temperature provides a different distribution of porphyringlobin species than reconstitution at 4 degrees C. Further changes in the species distribution of cold-reconstituted samples may be observed by gel electrophoresis when the samples are aged for 24h at room temperature. Chromatographic separation of such porphyringlobin samples on CM-Sephadex generally revealed five species with two in predominating amounts. It was consistently observed that over a period of 18 days, the faster moving of the two main components decreased in amount whereas the slower-moving component correspondingly increased. However, when the main components are separated, they remain homogeneous over the same length of time. The effect of light on porphyringlobin was also investigated. It was shown that porphyringlobin is photo-oxidized: as a result the porphyrin is destroyed together with most of the histidine, methionine and all of the tryptophan residues of the protein.

Light-induced protoporphyrin release from erythrocytes in erythropoietic protoporphyria.

“…They also suggest that the residues that lie in close proximity to the porphyrin ring are the first to be photodamaged (22). Light-induced dissociation of protoporphyrin from hemoglobin is supported by the studies of de Goeij et al (14) who showed that the amount of protoporphyrin not associated with hemoglobin increased after blood samples from patients with erythropoietic protoporphyria had been exposed to light.…”

“…In erythropoietic protoporphyria Lamola et al (16) propose that protoporphyrin in the erythrocytes is bound to intersubunit places on hemoglobin, whereas van Steveninck et al (15) suggest that protoporphyrin is bound to heme binding sites on globin. In the presence of globin, however, protoporphyrin is bound on the heme binding sites (16,22). In the present experiments ( Fig.…”

“…Protoporphyrin is photooxidized during irradiation (22). At 240 kJ/m2 the protoporphyrin concentration is about half the value of the nonirradiated sample.…”

Erythropoietic protoporphyria and lead intoxication: the molecular basis for difference in cutaneous photosensitivity. II. Different binding of erythrocyte protoporphyrin to hemoglobin.

“…The latter corresponded to the Soret maximium observed in the absorption spectra of these plrel)arations. The spectral characteristics agree exactly with those reported in the literature for similar preparations (13,(18)(19)(20).…”

A Label-free, Highly Sensitive and Selective Detection of Hemin Based on the Competition between Hemin and Protoporphyrin IX Binding to G-Quadruplexes

“…It can interact with many proteins, [23][24][25] and serves as a photodynamic agent in cancer therapy. 26,27 PPIX tends to aggregate into micelles in aqueous solution with low fluorescence, 28,29 but its fluorescence intensity is drastically increased when it binds to G-quadruplexes.…”