Kondo M, Hirota N, Takaoka T, Kajiwara M
Department of Nutrition and Biochemistry, Institute of Public Health, Tokyo, Japan.
Cell Biol Toxicol. 1993 Jan-Mar;9(1):95-105. doi: 10.1007/BF00755143.
The activities of four heme-biosynthetic enzymes, delta-aminolevulinic acid (ALA) synthase, ALA dehydratase, porphobilogen (PBG) deaminase, and ferrochelatase, were studied in five epithelial cell lines of normal rat liver origin (RL, RLC-10, RLC-24, M, Culb-TC) and five cell lines derived from Yoshida ascites hepatoma (JTC-1, JTC-2, JTC-15, JTC-16, JTC-24). The JTC series of hepatoma-derived cell lines exhibited decreased ALA synthase activity and increased ALA dehydratase activity, although the activities of all four enzymes and the Km values for their respective substrates varied widely from one cell line to another, a finding suggesting that specific regulatory mechanisms for porphyrin metabolism might operate in each cell type. M cells, which were transformed by 4-dimethylaminoazobenzene in vitro, gave the most abnormal Km values of heme-biosynthetic enzymes among all the cell lines studies, and were found to accumulate hematoporphyrin derivative (HpD).
研究了源自正常大鼠肝脏的五种上皮细胞系（RL、RLC - 10、RLC - 24、M、Culb - TC）和源自吉田腹水肝癌的五种细胞系（JTC - 1、JTC - 2、JTC - 15、JTC - 16、JTC - 24）中四种血红素生物合成酶，即δ-氨基乙酰丙酸（ALA）合酶、ALA脱水酶、胆色素原（PBG）脱氨酶和亚铁螯合酶的活性。尽管这四种酶的活性以及它们各自底物的米氏常数（Km值）在不同细胞系之间差异很大，但源自肝癌的JTC系列细胞系显示出ALA合酶活性降低和ALA脱水酶活性增加，这一发现表明卟啉代谢的特定调节机制可能在每种细胞类型中起作用。在所有研究的细胞系中，体外经4 - 二甲基氨基偶氮苯转化的M细胞，其血红素生物合成酶的Km值最为异常，并且发现其积累血卟啉衍生物（HpD）。
