| Abstract: | Human δ-aminolevulinic acid dehydratase (ALA-D) was purified 9 000-fold by salt precipitation, ion-exchange chromatography and gel filtration. These methods resulted into an electrophoretically and immunologically pure protein.The optimum pH of the enzyme is 6.6 and its Km with ALA : 4.8 × 10?4 M. The enzymatic activity was increased by thiol-containing substances, such as dithiothreitol (DTT), which protect the -SH groups of the protein. Zinc, a portion of the enzyme molecule, was partly lost during the purification procedure; its addition enhances the enzymatic activity.Determination of molecular weights and electron microscopy study are in favor of an octameric structure. |
