BLOOD DIGESTION IN THE MOSQUITO, ANOPHELES-STEPHENSI LISTON (DIPTERA, CULICIDAE) - PARTIAL CHARACTERIZATION AND POST-FEEDING ACTIVITY OF MIDGUT AMINOPEPTIDASES
BLOOD DIGESTION IN THE MOSQUITO, ANOPHELES-STEPHENSI LISTON (DIPTERA, CULICIDAE) - PARTIAL CHARACTERIZATION AND POST-FEEDING ACTIVITY OF MIDGUT AMINOPEPTIDASES
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DOI：
10.1002/arch.940150304
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发表时间：
1990-01-01
影响因子：
2.2
通讯作者：
BILLINGSLEY, PF
中科院分区：
文献类型：
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作者：
BILLINGSLEY, PF
氨肽酶活性的部分特点，从斯氏按蚊Liston已解剖吸血后30小时的中肠。在粗中肠匀浆上清液的氨肽酶表现出最佳的活性在pH 8.0和优先水解丙氨酸和亮氨酸末端的氨基酸底物。蛋氨酸、脯氨酸、赖氨酸和精氨酸末端底物水解，但谷氨酸不水解。Mg 2+、EDTA和低Ca 2+浓度对活性有刺激作用，而Mn 2+、Tris、1，10菲咯啉和较高的Ca 2+浓度则有抑制作用。在1%Triton X-100中均质化的中肠上清液显示活性增加两倍。中肠匀浆的差速离心证明了45%的总活性在一个假定的微绒毛颗粒和32%的可溶性部分。在Triton X-100中均质化后，超过92%的总活性被溶解。匀浆上清液中的活性仅限于一个具有较高分子量肩峰的主峰（Mr = 552，000）。经Triton X-100处理后，氨肽酶有三个明显的活性峰：一个高分子量的次峰（Mr = 552，000），两个主峰（Mr = 123，000和Mr = 32，000）。氨肽酶的活性增加后的血餐，在平行的胰蛋白酶活性的变化，表明其在二次消化血餐蛋白质的重要作用。
Aminopeptidase activity was partially characterized from midguts of Anopheles stephensi Liston which had been dissected 30 h after blood feeding. In crude midgut homogenate supernatants the aminopeptidases showed optimum activity at pH 8.0 and preferentially hydrolyzed alanine- and leucine-terminal amino acid substrates. Methionine, proline, lysine, and arginine terminal substrates were hydrolysed, but not glutamic acid. Activity was stimulated by Mg2+, EDTA, and low Ca2+ concentrations, while Mn2+, Tris, 1,10 phenanthroline, and higher Ca2+ concentrations were inhibitory. Supernatants from midguts homogenized in 1% Triton X-100 showed a two-fold increase in activity. Differential centrifugation of midgut homogenates demonstrated 45% of the total activity in a putative microvillar pellet and 32% in a soluble fraction. More than 92% of the total activity was solubilized after homogenization in Triton X-100. Activity in homogenate supernatants was restricted to one major peak (Mr = 552,000) with a higher molecular weight shoulder. Three distinct peaks of aminopeptidase activity were observed forllowing Triton X-100 treatment: a minor high molecular weight peak (Mr = 552,000), and two major peaks at Mr = 123,000 and Mr = 32,000 respectively. The activity of aminopeptidase increased after a blood meal, in parallel to the post-feeding changes in trypsin activity, indicating its important role in secondary digestion of blood meal proteins.