How and when to use the thiol conjugation approach: an introductory guide

A traditional method for linking proteins to molecules relies on the formation of a stable covalent bond between thiol (R-SH) and maleimide groups. When these functional groups are positioned on separate biomolecules (A & B) a hybrid conjugate AB (but not AA or BB) will form.

The thiol-maleimide reaction

The thiol-maleimide reaction

Despite other systems of conjugation being available (for instance, Lightning-Link® technology which relies on the presence of amine groups on your antibody or protein), the thiol-maleimide conjugation method could be the simplest approach if thiol groups are already present on your molecule of choice. If that is the case, your biomolecule could be easily conjugated to commercially available maleimide derivatives of protein labels or small molecules such as dyes. To help you better understand if the thiol-maleimide approach is the right one for you, we have recently published our new guide to thiol conjugation reactions, available on-demand for free.

Download this guide, if you want to know more about:

  1. The thiol-maleimide approach and its advantages
  2. The difference between thiol groups and disulfides and how thiol groups are generated
  3. How to find out if your sample contains free thiol groups
  4. Why thiol reducing agents such as Mercaptoethanol, DTT and TCEP are not interchangeable and how to know which one to choose in your application
  5. How to generate maleimide groups in your sample
  6. How to take advantage of a range of maleimide-activated labels in your assay
  7. How to measure the presence of maleimide groups
  8. How optimizing the number of reactive groups can improve conjugation efficiency
  9. How to desalt your sample from reactants, reducing agents or stabilizers which could interfere with your reaction

Download the Guide