抄録
δ-aminolevulinic acid (ALA) synthetase and heme synthetase activities in erythroblasts of 14 patinets with primary sideroblastic anemia were measured. 14C-glycine incorporation into heme in erythroblasts was also studied in these patients.
Among these patients, 2 patients responded to the vitamin B6 treatment with an improvement of anemia. One patient was considered as to belong to the hereditary type. ALA synthetase activity of the bone marrow erythroblasts was measured by the amounts of 14C-α-ketoglutarate or 14C-succinyl-CoA incorporated into ALA in the bone marrow cell homogenate or in the deoxycholate extract of the bone marrow cell mitochondrial fraction. ALA formed from these precursors was separated by using Dowex-1 or Dowex 50 columns.
ALA-synthetase activity was markedly reduced to one tenth or to one twentieth of normal in 5 cases. In other 9 cases, the enzyme activity was reduced to the half or to one third of normal. Incorporation of 14C-glycine into heme was also reduced in all these cases, although the degree of the reduction was not so marked as compared to the reduction of the ALA-synthetase activity. Heme synthetase activity of erythroblasts was differed considerably by each case. They showed increased, normal, and reduced activities.
It was concluded that the ALA-synthetase activity was reduced in all cases of the sideroblastic anemia, and that this reduction of ALA-synthetase activity was intimately related to the various hematologic pictures characteristic to this disorder.
