Zinc-protoporphyrin

Zinc protoporphyrin in blood After 1 month exposure 2 50 pg/100 ml erythrocytes or lOOpg/IOOmI blood B... 

PbB concentrations reflect the absorbed dose of lead. However, the interpretation of PbB data depends on a knowledge of the past history of exposure to lead. This is because in the body, bone constitutes the major lead sink and this results in lead having a long body half-life. Thus, in the absence of intense exposure to lead for a considerable period up to its body half-life, the PbB concentrations reflect recent lead exposures. However, if intermittent exposure to lead is occurring in several distinct environments, the PbB concentration reflects both recent and past exposures to lead. Thus, biological effects for populations with the same PbB concentrations may not be the same since different exposure times scales may be involved. This is the reason why free erythrocyte protoporphyrin (FEP) and erythrocyte zinc protoporphyrin (ZPP) have been used as additional biological markers since their elevation is more related to chronic lead exposure than acute lead exposure (see Section 2.7). 

Rat (albino) 4 wk ad lib (W) Hemato 109 M (decreased ALAD activity and hemoglobin increased urinary excretion of ALA and increased blood zinc protoporphyrin) Flora etal. 1993 PbAc... 

Inhibition of ferrochelatase in the heme pathway causes accumulation of protoporphyrin in erythrocytes (CDC 1985). Most protoporphyrin in erythrocytes (about 90%) exists as zinc protoporphyrin (ZnPP). This fraction is preferentially measured by hematofluorometers. Extraction methods measure all the protoporphyrin present, but strip the zinc from the ZnPP during the extraction process. For this reason,... 

Chisolm JJ Jr, Brown DH. 1979. Micromethod for zinc protoporphyrin in erythrocytes Including new data on the absorptivity of zinc protoporphyrin and new observation in neonates and sickle cell disease. Biochem Med 22 214-237. 

Froom P, Kristal-Boneh E, Benbassat J, et al. 1998. Predictive values of determinations of zinc protoporphyrin for increase blood lead concentrations. Clin Chem 44 1283-1288. 

Joselow MM, Flores J. 1977. Application of the zinc protoporphyrin (ZP) test as a monitor of occupational exposure to lead. Am Ind Hyg Assoc J 38 63-66. 

Lilis R, Eisinger J, Blumberg W, et al. 1978. Hemoglobin, serum iron, and zinc protoporphyrin in lead-exposed workers. Environ Health Perspect 25 97-102. 

Odone P, Castoldi MR, Guercilena S, et al. 1979. Erythrocyte zinc protoporphyrin as an indicator of the biological effect of lead in adults and children. In International Conference on Management and Control of Heavy Metals in the Environment, London, United Kingdom, September. Edinburgh, UK CEP Consultants, Ltd., 66-69. 

Zinc protoporphyrin IX is a normal metabolite that is formed in trace amounts during haem biosynthesis. However, in iron deficiency or in impaired iron utilization, zinc becomes an alternative substrate for ferrochelatase and elevated levels of zinc protoporphyrin IX, which has a known low affinity for oxygen, are formed. This zinc-for-iron substitution is one of the first biochemical responses to iron depletion, and erythrocyte zinc protoporphyrin is therefore a very sensitive index of bone-marrow iron status (Labbe et ah, 1999). In addition, zinc protoporphyrin may regulate haem catabolism by acting as a competitive inhibitor of haem oxygenase, the key enzyme of the haem degradation pathway. However, it has been reported... 

Ostrowski, S.R., E.W. Gunter, and T.D. Matte. 1990. Blood lead and zinc protoporphyrin levels in donkeys and mules near a secondary lead smelter in Jamaica, 1987-88. Veterin. Human Toxicol. 32 53-56. 

Fig. 2.149. HPLC elution profile of the red pigment from Parma ham. Traces 1 and l, standard solutions. Traces 2 and 2, Parma ham extract. Peaks are as follows H, hemin Z, zinc protoporphyrin IX and P, protoporphyrin IX. Reprinted with permission from J. Wakamatsu et al. [323].

A 48-year-old man developed abdominal colic, muscle pain, and fetigue. Following a 3-week hospitalization, acute intermittent porphyria was initially diagnosed based on a high level of urinary 5-aminolevulinic acid. Subsequent analysis of the patient s circulating red blood ceUs revealed that 70% contained elevated levels of zinc protoporphyrin, and the diagnosis was corrected. The correct diagnosis is most likely to be... 

Answer C. Lead inhibits both ferrochelatase (increasing the zinc protoporphyrin) and ALA dehydrase (increasing 5-ALA). 

Test results that show bioabsorption of toxicants (e.g., blood Pb levels) or reveal early medical effects of overexposure that do not constitute a disease entity (e.g., blood zinc protoporphyrin levels) can be given to the environmental engineer in personally identifiable form. Biological monitoring test results that identify a disease state (e.g., oligospermia) constitute confidential information about the health status of the individual which is not to be... 

Selikoff, I. J., Zinc Protoporphyrin in Blood as a Biological Indicator of Chronic Lead Toxication, J. Environ. Pathol. Toxicol., 1978, L, 897-910. 

Chromatographic determination of protoporphyrins in erythrocytes has the same indications as the spectrophotometric one. In addition, the method enables the differentiation between zinc-protoporphyrin and (metal-)free protoporphyrin. The first is elevated in iron deficiency and lead intoxication, the second in erythropoietic protoporphyria. 

Standard solution 100 pi protoporphyrin solution, 100 pi zinc protoporphyrin solution and DMSO are mixed to achieve a volume of 5 ml. The volume of protoporphyrin solution may be corrected for decay (Table 7.3.7). 

Patients with erythropoietic protoporphyria show high values of free protoporphyrin. Iron deficiency and lead intoxication augment zinc protoporphyrin. 

Each laboratory should establish its own reference values. Those given below can only be interpreted as a guide. Free protoporphyrins in erythrocytes are rarely detectable in healthy individuals. Zinc protoporphyrin <1.3 pmol/1 (mean 2SD), free protoporphyrin < 0.2 pmol/1 (detection limit). 

As stated before, increased zinc protoporphyrin is seen in iron deficiency and lead intoxication. The quantitative values are in the range of 2-6 pmol/1. Erythropoietic protoporphyria patients show an increase in protoporphyrin in the range of 6-50 pmol/1. In case of complicating liver disease, the value can increase even further. 

ICP-MS was used for the detection of biologically significant metalloporphyrins separated by RP-HPLC by Kumar et al. [43]. Cobalt protoporphyrin (CoPP), iron protoporphyrin (hemin) and zinc protoporphyrin (ZnPP) were separated using a Cl column (due to the relatively large molecular mass of the compounds) and a mobile phase optimised with 68% methanol at pH 4.5 (Fig. 2). Detection limits were... 

The insertion of ferrous iron into the porphyrin ring in the biosynthesis of heme is catalyzed by the enzyme ferrochelatase. A deficiency in ferrochelatase activity results in an accumulation or the excretion of unchelated protoporphyrin in patients with erythrohepatic protoporphyria. Ferrochelatase catalyzes the synthesis of a range of metalloporphyrins,628 and, for example, produces zinc protoporphyrin in erythrocytes of patients with iron-deficiency anaemia. 

Hemoglobin chains of one type (a or /J) were substituted with closed shell zinc protoporphyrin (ZnP), and chains of the opposite type were oxidized to the... 

The construction of an artificial protein-protein complex is an attractive subject to elucidate the electron-transfer process in biological systems. To convert Mb into an electron-transfer protein such as cytochromes, Hayashi and Ogoshi (101) prepared a new zinc Mb having a unique interface on the protein surface by the reconstitutional method as shown in Fig. 27. The modified zinc protoporphyrin has multiple functional groups, carboxylates, or ammonium groups, at the terminal of the two propionates. Thus, the incorporation of the... 

The photochemical dechlorination of 4-chlorobiphenyl in the presence of anthracene and triethylamine is supposed to proceed via two electron transfer steps, first from triethylamine to excited anthracene and then from the anthracene radical anion to the aryl halide410. This type of mechanism is also operative in the dechlorination of 4-chlorobiphenyl, 4,4 -dichlorobiphenyl, 1,3,5-trichlorobenzene, 1,2,3,5-tetrachloroben-zene and pentachlorobenzene photosensitized by visible dyes (protoporphyrin IX, acriflavin, rose bengal, zinc protoporphyrin, methylene green) in the presence of triethylamine411. The various steps of the mechanism are summarized in equations 112-115. A mechanistic alternative is that the excited photosensitizer transfers an electron directly to the aryl chloride and becomes regenerated by electron transfer from the amine. 

Figure 10.2 shows a Stern-Volmer plot for the fluorescence intensity quenching by oxygen of zinc protoporphyrin IX embedded in the heme pocket of apomyoglobin (Mbdes Fe). The slope of the plot yields Ksv and A q values of 15.96 M-1 s-1 and 7.6 x 109 M-1 s-1,... 

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