Which isotopes can I use to radiolabel IgG after chelation using GlyCLICK?
The GlyCLICK technology can be used to conjugate IgG with Desferrioxamine (DFO) using the GlyCLICK DFO kit. The DFO is a chelating agent for radiolabeling with the radioisotope Zirconium-89 (89Zr) for PET-imaging. The Azide Activation kit can be used to conjugate a chelator of choice if it is alkyne-modified (carrying for example DIBO, DBCO or BCN) to be compatible with the click chemistry.
Can I freeze antibodies after biotinylation using GlyCLICK?
Problems can arise from freezing of the conjugates. We cannot guarantee the quality after freezing and therefore recommend storage at +4°C.
What fluorescent labels can I use with the GlyCLICK technology?
GlyCLICK is available in kit formats with AlexaFluor®488, AlexaFluor®555, AlexaFluor®647 or in the Azide Activation kit format for conjugation of a label of choice. With the fluorescent label being alkyne-modified (carrying for example DIBO, DBCO or BCN) it is possible to combine it with the GlyCLICK azide activation kit.
How do I perform quality control of the conjugation process?
Characterization using LC-MS will give a complete and clear picture of mass shift associated with successful conjugation if the antibody is analyzed reduced or fragmented. LC or LC-MS analysis of HC from a reduced sample or scFc fragments generated by FabRICATOR digestion provides distinct elution peaks for conjugated scFc or mass shifts corresponding to the degree of labelling (DOL) following conjugation. On the application page you can see an example of such analysis. Analysis of fluorescently labeled antibodies can also be performed by absorbance measurements and calculate the DOL using the Extinction coefficient for the antibody and the label and the correction factor for the label.
Why do I need to use an alkyne-functionalized label with GlyCLICK?
The final step of GlyCLICK labeling kit is based on a copper free click reaction (SPAAC) and it is a strain promoted reaction between an azide and an alkyne-carrying label. As the name indicates the reaction occurs spontaneously due to the strained bond angles. The use of this click reaction that forms stable conjugates, allows you to freely choose label or payload to combine with your IgG as long as it is alkyne-functionalized. Several alkyne-carrying labels are commercially available with cyclooctyne structures such as DIBO, DBCO or BCN.
What is the smallest amount of IgG that I can process using the 250 ug kit?
The GlyCLICK 250 ug kit is optimized for 250 ug of IgG as a starting material. We do not recommend using less than 100 ug of starting material in a minimum of 100µL to achieve proper end-over-end mixing on the GlycINATOR columns. Please contact support@genovis.com for assistance if you want to process smaller amounts then 100µg.
For how long can I store azide activated antibodies?
The stability of azide activated material varies depending on the antibody and if stabilizing agents have been added. In our labs we have stored azide activated antibodies in TBS buffer without any additives at +4°C for over two years. The azide activation was still OK, and the click reaction generated antibodies with DOL=2. If azide is added as a preservative during long-term storage, it must be removed prior to click reaction.
What is the conjugation efficacy using GlyCLICK?
All the steps (deglycosylation, azide activation and click reaction) in GlyCLICK are highly efficient. Normally, all molecules are conjugated when using GlyCLICK, resulting in DOL=2. On the application page we have shown by MS-analysis that all molecules have been conjugated and there is no remaining un-conjugated material.