A 1332 bp full length cDNA encoding Teladorsagia circumcincta isocitrate lyase (TciICL) and a 1575 bp full length cDNA encoding T. circumcincta malate synthase (TciMS) were cloned, expressed in Escherichia coli and the recombinant proteins purified. The predicted TciICL protein of 444 amino acids was present as a single band of about 52 kDa on SDS-PAGE and the recombinant TciMS of 525 amino acids formed a single band about 62 kDa. Multiple alignments of the combined bifunctional TciICL-MS protein sequence with homologues from other nematodes showed that the greatest similarity (89–92 %) to the homologues of Ancylostoma ceylanicum, Haemonchus contortus and Haemonchus placei and 71–87 % similarity to the other nematode sequences. The 3-dimensional structures, binding and catalytic sites were determined for TciICL and TciMS and shown to be highly conserved. Substrate and metal ion binding sites were identified and were completely conserved in other homologues. TciICL was confirmed as a functional enzyme. At 30 °C, the optimum pH was pH 7.5, the V_max was 275 ± 23 nmoles.min⁻¹. mg^-1 protein and the apparent K_m for the substrate isocitrate was 0.7 ± 0.01μM (mean ± SEM, n = 3). Addition of 10 mM metal ions (except Mg²⁺) or 1 mM inhibitors reduced the recombinant TciICL activity by 60–90 %. Antibodies in both serum and saliva from field-immune, but not nematode-naïve, sheep recognised recombinant TciICL in ELISA, supporting similar antigenicity to that of the native enzyme.

甲1332 bp的全长cDNA编码Teladorsagia circumcincta异柠檬酸裂合酶（TCI ICL）和1575碱基对的全长cDNA编码T. circumcincta苹果酸合酶（TCI MS）进行克隆，在表达大肠杆菌和纯化的重组蛋白。预测的444个氨基酸的Tci ICL蛋白以约52 kDa的单条带存在于SDS-PAGE上，而525个氨基酸的重组Tci MS形成了约62 kDa的单条带。组合的双功能Tci ICL-MS蛋白序列与其他线虫同源物的多重比对表明，与其他线虫同源物最大相似（89–92％）钩虫ceylanicum，捻转血矛线虫和捻转血矛placei和71-87％的相似性的其他线虫的序列。确定了Tci ICL和Tci MS的3维结构，结合和催化位点，并显示高度保守。底物和金属离子结合位点已被鉴定，并在其他同源物中完全保守。Tci ICL被确认为功能性酶。在30°C下，最适pH为7.5，V _max为275±23 nmoles.min ^-1。mg ^-1蛋白和表观K _m底物异柠檬酸根的C值为0.7±0.01μM（平均值±SEM，n = 3）。添加10 mM金属离子（Mg ²⁺除外）或1 mM抑制剂会使重组Tci ICL活性降低60–90％。来自野外免疫但未经线虫感染的绵羊血清和唾液中的抗体均在ELISA中识别了重组Tci ICL，与天然酶具有相似的抗原性。