The conjugation and modification reactions used to cross-link proteins or couple labels to proteins, such as biotin, enzymes, and fluorescent dyes, require certain conditions, including pH and chemical composition for optimal conjugation. Many common buffers routinely used in laboratories have an inhibitory effect on conjugation reactions; for example, Tris buffers inhibit coupling to amines.

These six reaction-specific buffers provide the optimal conditions for protein labelling, modification and cross reaction:
Optimizer Buffer™-I is for amine reactive groups
Optimizer Buffer™-II has a high pH and is designed for the sulfhydryl reactive groups
Optimizer Buffer™-III is designed for sulfhydryl reactive groups
Optimizer Buffer™-IV is designed for carboxyl reactive reagents
Optimizer Buffer™-V is a modified acetate buffer that is specific for carbohydrate reactive groups
Optimizer Buffer™-VI is an alkaline buffer specific for the formation of Schiff’s base between amines and glyoxal groups