Beta-ketothiolase deficiency in a family confirmed by in vitro enzymatic assays in fibroblasts.
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Biomedical subjects
Publications and source records attributed to T Vulsma.
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1. A rapid isolation procedure with a high yield for pure myeloperoxidase (donor:H2O2 oxidoreductase, EC 1.11.1.7) from normal human leucocytes is described. The enzyme was solubilized from leucocytes with the detergent, cetyltrimethylammonium bromide, and purified to apparent homogeneity. The yield of the enzyme was 17% with an absorbance ratio A430nm/A280nm = 0.85. 2. The purified enzyme showed three isoenzyme bands after polyacrylamide gel electrophoresis; ultracentrifuge studies indicated one homogeneous band with a molecular weight of 144 000. After reduction of myeloperoxidase, sodium dodecyl sulfate gel electrophoresis resolved an intense band (63 000 daltons) and a weak band (81 000 daltons). 3. The carbohydrate content of the enzyme was at least 2.5%. Mannose, glucose and N-acetylglucosamine were present. The amino acid composition is reported. 4. The EPR spectrum exhibited a high-spin heme signal with rhombic symmetry (gx = 6.92, gy = 5.07 and gz = 1.95). Upon acidification this signal was converted into a signal with more axial symmetry (g perpendicular = 5.89). At high pH (9.5) the EPR spectrum of the enzyme only shows low-spin ferric heme resonances. The circular dichroism spectra of ferric and ferrous myeloperoxidase in the visible and ultraviolet region show maxima and minima in ellipticity.
1. EPR spectra of human granulocytes (4 - 10(8) cells per ml) show an intense high-spin ferric heme signal with rhombic symmetry (gx = 6.90 and gy = 5.07) for the heme group. These g-values are identical to those of partially purified myeloperoxidase and thus the signal is derived from ferric myeloperoxidase. In chicken granulocytes, which contain little or no myeloperoxidase, only an axial type of heme iron signal, weak in intensity, can be detected at g = 6.0. 2. Upon phagocytosis of latex particles by human granulocytes the high-spin heme signal with rhombic symmetry is slowly converted into a signal with axial symmetry (gx = gy = 6.0), showing that the EPR signals of myeloperoxidase in the intact cell can be used to study the involvement of the enzyme in metabolic changes during phagocytosis.