Showing papers on "Protoporphyrins published in 1994"
TL;DR: The present paper describes the structure of horse-spleen apo-ferritin cocrystallized with Sn-protoporphyrin IX, the iron-storage protein, which comprises 1613 non-H atoms, two Cd atoms and 170 solvent molecules.
Abstract: Ferritin, the iron-storage protein, binds porphyrins, metalloporphyrins and the fluorescent dyes ANS (8-anilino-1-naphthalenesulfonic acid) and TNS (2-p-toluidinyl-6-naphthalenesulfonic acid), similarly to apo-myoglobin. Octahedral crystals of horse-spleen apo-ferritin (HSF; 174 amino acids) complexes prepared by the addition of haem, hematoporphyrin or Sn-protoporphyrin IX to a solution of apo-ferritin crystallize in space group F432 with cell parameter a = 184.0 A. X-ray crystallographic analysis of single crystals prepared from a mixture containing haem or Sn-protoporphyrin IX shows that the haem-binding sites in these crystals are occupied by protoporphyrin IX, which is free of metal, rather than by the original metalloporphyrin. The present paper describes the structure of horse-spleen apo-ferritin cocrystallized with Sn-protoporphyrin IX. The 6797 reflections up to 2.6 A resolution used in the refinement were obtained from a data set recorded on a Nicolet/Xentronics area detector with Cu Kalpha radiation from a Rigaku RU 200 rotating anode. The final structure comprises 1613 non-H atoms, two Cd atoms and 170 solvent molecules. Four residues are described as disordered. The root-mean-square deviations from ideal bond lengths and angles are 0.013 A and 2.88 degrees, respectively. Protoporphyrins are observed in special positions on the twofold axes of the ferritin molecule with a stoichiometry of 0.4 per subunit.
24 citations
TL;DR: Inductively coupled plasma-mass spectrometry is investigated for the detection of metalloporphyrins separated by liquid chromatography and zinc protoporphyrsin is determined from the whole blood of a lead-poisoned patient.
Abstract: Inductively coupled plasma-mass spectrometry is investigated for the detection of metalloporphyrins (cobalt protoporphyrin, hemin, and zinc protoporphyrin) separated by liquid chromatography. A Hypersil SAS C1 column with mobile phase containing 68% methanol at a pH of 4.5 is used. The detection limits obtained are in the nanogram range for cobalt and zinc protoporphyrins, whereas for hemin, detection limits are in the microgram range. The accuracy of the method is evaluated by determining zinc protoporphyrin from the whole blood of a lead-poisoned patient.
16 citations
TL;DR: By this method, the amounts of these analytes in erythrocytes from normal or abnormal subjects can be determined more accurately than by conventional methods.
Abstract: In this new method for simultaneous separation and quantification of free and metal-chelated porphyrins in blood, the porphyrins are extracted from blood samples with a mixture of diisopropylamine:water:methanol (25:100:900, by vol) and separated by HPLC elution. The data are collected in three-dimensional form with a microcomputer. This method permits a high recovery of protoporphyrin (PP) and Zn-chelated PP as well as heme from blood. By this method, the amounts of these analytes in erythrocytes from normal or abnormal subjects can be determined more accurately than by conventional methods.
14 citations