Topic
Protoporphyrin IX
About: Protoporphyrin IX is a research topic. Over the lifetime, 2250 publications have been published within this topic receiving 65544 citations. The topic is also known as: PpIX.
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TL;DR: The data suggest that in liver the binding to peripheral benzodiazepine receptors is related to cholesterol translocation and the interaction of ligands with these receptors may play a role in the complex mechanism of regulation of cholesterol traffic between liver mitochondrial membranes.
30 citations
TL;DR: A biochemical mechanism was involved in PPIX-SDT in vivo, and the free radicals produced by the synergistic treatment destroying the anti-oxidative system of tumor cells in vivo may play an important role in this action.
30 citations
TL;DR: It is suggested that cytochrome P-450 content may be decreased during copper deficiency due to a decrease in ferrochelatase activity and a subsequent defect in heme biosynthesis.
Abstract: Drugs and heavy metals may alter the synthesis of hemo-proteins by either inducing or inhibiting various enzymes in the heme biosynthetic pathway (Fig. 1) (Tephly et al., 1971; Tephly et al., 1973). Porphyrogenic drugs and inducers of the hepatic hemo-protein, cytochrome P-450, such as phenobarbital, induce hepatic δ-aminolevulinic acid synthetase (ALAS), the initial and proposed rate-limiting enzyme of this pathway (Granick and Urata, 1963; Baron and Tephly, 1969; Tephly et al., 1973). Ferrochelatase (heme synthetase, protoheme ferro-lyase, EC 4.99.1.1), the terminal enzyme in the heme pathway, is located on the inner mitochondrial membrane (Jones and Jones, 1968; McKay et al., 1969) and catalyzes the formation of heme from protoporphyrin IX and ferrous iron (Labbe and Hubbard, 1960). This enzyme, like ALAS, is inducible (Hasegawa et al., 1970; Tephly et al., 1971), and may be subject to product inhibition by heme (Jones and Jones, 1970). Heme which is formed through ferrochelatase is then available for synthesis of cytochrome P-450 and other hemoproteins. Tephly and co-workers (Tephly and Hibbeln, 1971; Tephly et al., 1972) have reported that cobalt treatment produces a substantial decrease in the level of hepatic cytochrome P-450.
30 citations
TL;DR: Protoporphyrin IX fluorescence in experimentally induced endometriosis lesions after intravenous and oral delivery of 5-aminolevulinic acid was significantly greater than the fluorescence detected in adjacent normal peritoneum.
29 citations
TL;DR: The final steps in heme synthesis take place within mitochondria while the acceptor apoproteins are synthesized on the endoplasmic reticulum, and heme export from mitochondria is dependent on protein in the suspending medium.
Abstract: The final steps in heme synthesis take place within mitochondria while the acceptor apoproteins are synthesized on the endoplasmic reticulum. When 14C-δ-aminolevulinic acid is used as a heme precursor in intact rats, measurable 14C-heme is found to be associated with the microsomes within 10 min of intraperitoneal injection. This rapid transfer of heme from mitochondria was studied in vitro using isolated rat liver mitochondria, and protoporphyrin IX and 59Fe as heme precursors. These mitochondria synthesize heme when suspended in whole cell sap and this is only partially reduced by substituting Sephadex G-25 filtered cell sap or sucrose. Mitochondria incubated in G-25 filtered cell sap or sucrose synthesize equivalent amounts of heme but those in sucrose export little heme into the surrounding medium. Heme export from mitochondria is dependent on protein in the suspending medium. In cell sap, heme is associated with multiple proteins and no single carrier was identified. Heme probably makes its way from ...
29 citations