Srivastava P, Pandey V C
Division of Biochemistry, Central Drug Research Institute, Lucknow, India.
Exp Parasitol. 1998 Jan;88(1):60-3. doi: 10.1006/expr.1998.4193.
Intraerythrocytic stages of cell-free Plasmodium knowlesi possess significant activities of heme biosynthetic enzymes, viz. delta-aminolevulinic acid synthase (delta-ALAS), delta-aminolevulinic acid dehydrase (delta-ALAD), ferrochelatase (FC), and tryptophan pyrrolase (enzyme representing free heme pool). delta-Aminolevulinic acid synthase and FC showed higher activities in schizont than in ring trophozoite stage. Uninfected monkey erythrocytes did not possess the above-mentioned enzyme activities; on the contrary, leucocytes showed detectable enzyme activities. delta-Aminolevulinic acid synthase was not appreciably inhibited by different antimalarials. Succinyl acetone and hemin exhibited a concentration-dependent inhibition of delta-ALAD and delta-ALAS, respectively.
无细胞诺氏疟原虫的红细胞内阶段具有血红素生物合成酶的显著活性，即δ-氨基乙酰丙酸合酶（δ-ALAS）、δ-氨基乙酰丙酸脱水酶（δ-ALAD）、亚铁螯合酶（FC）和色氨酸吡咯酶（代表游离血红素池的酶）。δ-氨基乙酰丙酸合酶和FC在裂殖体阶段的活性高于环状滋养体阶段。未感染的猴红细胞不具有上述酶活性；相反，白细胞显示出可检测到的酶活性。不同的抗疟药对δ-氨基乙酰丙酸合酶没有明显抑制作用。琥珀酰丙酮和血红素分别对δ-ALAD和δ-ALAS表现出浓度依赖性抑制作用。
