Human Angiopoietin 2 protein, His tag

Angiopoietin is part of a family of vascular growth factors that play a role in embryonic and postnatal angiogenesis. Angiopoietin cytokines are involved with controlling microvascular permeability, vasodilation, and vasoconstriction by signaling smooth muscle cells surrounding vessels. There are now four identified angiopoietins: ANGPT1, ANGPT2, ANGPT3, ANGPT4. Angiopoietin 2 (ANGPT2) promotes cell death and disrupts vascularization. Yet, when it is in conjunction with vascular endothelial growth factors, or VEGF, it can promote neo-vascularization. Besides, TEK Tyrosine Kinase (Tie2) has been identified as an interactor of ANGPT2, thus a binding ELISA assay was conducted to detect the interaction of recombinant human ANGPT2 and recombinant human Tie2. Briefly, ANGPT2 were diluted serially in PBS, with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to Tie2-coated microtiter wells and incubated for 2h at 37ºC. Wells were washed with PBST and incubated for 1h with anti-ANGPT2 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody, wells were aspirated and washed 3 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37ºC. Finally, add 50 μl stop solution to the wells and read at 450nm immediately. The binding activity of ANGPT2 and Tie2 was in a dose dependent manner.