家蚕中的5-氧脯氨酸酶及保幼激素类似物对它的影响

5-L-OXOPROLINASE IN BOMBYX MORI AND THE EFFECTS OF JUVENILE HORMONE ANALOGUE ZR-512

本工作首次在家蚕Bombyx mori的马氏管、中肠、丝腺及脂肪体等组织中测到了γ-谷氨酰循环中一个关键酶——5-L-氧脯氨酸酶的活力。该酶以马氏管中活力最高,在蚕的中肠、血淋巴中均存在有游离的5-氧脯氨酸。观察了保幼激素类似物(JHA)处理后,家蚕中肠、丝腺和脂肪体中5-L-氧脯氨酸酶活力的变化,同时观察了血淋巴中5-氧脯氨酸含量的变化。对该酶及γ-谷氨酰循环在蚕体中氨基酸转运上的可能作用进行了讨论。

Activities of 5-L-oxoprolinase in the Malpighian tubules, midgut, posterior silkgland and fat body of Bombyx mori were determined, using 14C-5-L-oxoproline as the substrate. The specific activity in Malpighian tubules was higher than iliat in any other tissues. The activities in midgut, posterior silkgland and fat body chmged during the 5th instar. The contents of free 5-oxoproline in midgut and haemolymph were also determined. The effects of JHA(ZR-512) on the enzymic activities in different tissues and the contents of free 5-oxopniline in haemolymph were observed. The study confirms the presence of Y-glutamyl cycle in silkworm and the possible functions of this cycle in arnino acid transportation in silkworm are discussed.