What is EDC and NHS?

EDC, in conjunction with NHS allows, for 2-step coupling of two proteins without affecting the carboxyls of the second protein. First, EDC activates carboxyl groups and forms an amine reactive O-acylisourea intermediate that spontaneously reacts with primary amines to form an amide bond and an isourea by-product.

What is the purpose of adding the coupling reagent EDCI?

1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC, EDAC or EDCI) is a water-soluble carbodiimide usually handled as the hydrochloride. It is typically employed in the 4.0-6.0 pH range. It is generally used as a carboxyl activating agent for the coupling of primary amines to yield amide bonds.

What is the role of carbodiimide in the synthesis of amide?

Amide formation mechanism The formation of an amide using a carbodiimide is a common reaction, but carries the risk of several side reactions. The O-acylisourea 2 can react with an additional carboxylic acid 1 to give an acid anhydride 5, which can react further to give the amide 3.

When does the coupling reaction of EDC take place?

This is because the adsorption of solvent by the collagen gel, protonation of carboxylate anion, and hydrolysis of EDC is at its most optimum condition for the coupling reaction when the ethanol mole concentration is 0.12.

What is the coupling rate of EDC / NHS?

The re-crosslinking of the collagen gel showed an increase in the crosslinking rate, but did not show further increase when the coupling reaction was executed for the third time. This implied that the highest possible crosslinking rate for the intra- and interhelical is approximately 60% when EDC/NHS is used.

How to coupling an amino acid with EDC?

Coupling with EDC 1 Dissolve the N-protected amino acid and the amino acid ester to be coupled in dichloromethane (DCM). 2 Cool the mixture in an ice bath. 3 Add 1.2 equivalents of EDC and stir the mixture. 4 When the reaction is complete, wash the mixture with water to remove excess EDC and urea by-product.

What kind of coupling agent is used for DCC?

One of the strategies is to use a coupling agent such as DCC (N,N’-dicyclohexane carbodiimide) or EDC (1-Ethyl-3- (3-dimethylaminopropyl)carbodiimide. Both are carbamides (RN=C=NR) which prevent the acid-base reaction and make the carboxylic acid susceptible to a nucleophilic attack.