Some properties of fbl 塾 c ac 孟 d 予 glutamyl hydrolase ( conjugase ) [ EC 3, 4. 22. 垂2]and dihydrofblate reductase [ EC l. 5 . 1. 3 ] in silkworm larva1 bodies were investigated . The c 叩 jugase enzyme had an optimum pH of 7. 8 , and an optimum tcmperature of 50℃ , The enzymatic activity was stinulated in the presence of 2 − mercaptoethano1 , K ' and Mg2 ' , but inhibited by p − hydroxyinercuriphenyl sulfonate , Co2 申 , Zn2 + and Fe2 ' . This conjugase converted pteroylpenta − yL − glutamic

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... to pteroyl moneglutamic acid exclusively , and the Kln value was about 9. 6mM when measuB 巳d at pH7 , 8, 37℃ with pteroy 堊 tri 一 繁 L − g 歪 utamic acid as the substrate , The dihydrofolate red 睦 ctase in the silkworm fat body required NADPH , had an optimum pH of 4. 5 -75 , and an optimum temperature ef 35 ℃ . lts actvity was stimulated in the presence of 2 − mercaptoetha 皿 ol , gu 跏 idine , Mgz + −amd high concentration of K ' and Na + , but inhibited by 戸 chloromercu 曲 enzoate , formamide and Co2 + . The K 洫 v 紐ue measured at pH5 . 0, 30 ℃ , was about 2 . 7mM when dlhydropteroyl glutamic acid was used as the subsn ' ate . Key words :Bombyx 1皿 ori , folic acid y − glutamyl hydrolase , dihydrofc }1ate 【eductase ( Reeeiレed / une 23, 2000 )