I bought the human leucine-rich α2 glycoprotein 1 (LRG1) ELISA test kit (purchased from Jianglai, JL14662) to detect the content of LRG1 protein (purchased from MedChemExpress, HY-P7016). However, the test results do not have a signal value. The test layout and signal value, as well as the data processing results of the standard curve quality control are as follows:
May I ask:
1. What is the reason why the ELISA kit cannot detect LRG1 protein;
2. What is the difference between the two reagents HY-P70166 (MCE) and HY-P70175 (MCE) from MedChemExpress? I want to try whether the protein with the catalog number HY-P70175 can be detected, but HY-P70175 has one more Fc than HY-P7016. Will the double antibody sandwich method be more difficult to bind?
Binbin Lee
Because the detection principle of the kit you used is different from that of MedChemExpress (MCE), the signal cannot be detected. Some ELISA kits have been unable to identify recombinant protein samples. It is recommended that you purchase a small package of recombinant LRG1 protein (HY-P70175, MCE) for trial use.
The recombinant LRG1 protein with Fc tag (HY-P70166, MCE) is not absolutely impossible to detect with ELISA double antibody sandwich method, but it does need to be cautious. The main reason is related to the interference that may be caused by the characteristics of Fc tag: for example, non-specific interaction with secondary antibody. If the fusion site of Fc tag is close to the epitope recognized by capture antibody or detection antibody on LRG1, it may mask the epitope, hinder the specific binding of antibody to LRG1, and reduce the sensitivity or accuracy of detection.
In contrast, it is more recommended to give priority to recombinant protein without Fc tag, or use specific antibodies against non-tag region of LRG1 to reduce the risk of interference.
The answer to this question comes from MedChemExpress (MCE) Technical Support.