Carboxylates thiols

What is not included here is the need also to protect any vulnerable functional groups in the amino acid side-chains. A range of methods is available to protect amino, carboxyl, thiol, and hydroxyl groups and prevent them reacting during the amide bond synthesis. Such groups also have to be removed after their job is done, using conditions that do not... 

There are many electrophiles which not only terminate living polymer chains but also produce end-group substitution. For example, macromolecules with hydroxyl, carboxyl, thiol, or chlorine termini can be prepared by reacting living polymers with such compounds as epoxides, aldehydes, ketones, carbon dioxide, anhydrides, cyclic sulfides, disulfides, or chlorine (15-23). However, primary and secondary amino-substituted polymers are not available by terminations with 1° or 2° amines because living polymers react with such functionalities (1.). Yet, tert-amines can be introduced to chain ends by use of -N-N-di-methylamino-benzaldehyde as the terminating agent (24). 

Carboxylate, thiols, or amino moities are a few examples of ionizable groups at physiological pH. The propensity of an ionizable group to lose a proton is measured by the pKa, which is defined by the following ... 

The second hierarchical level of the nanostructure (1—4nm) can be a rather complicated stmcture. It stabilizes the nanosized carrier by modifying the surface with biocompatible coverage (polyacrylamide, silica, hydroxyapatite, titanium, or aluminum oxide, etc.). The presence of a modifying layer retains a high specific surface of the nanoparticles and allows the necessary chemical functionalization, for example, with hydroxyl, carboxyl, thiol, and amino groups. 

In this article, the representative analytical methods for several functional groups such as amino, hydroxy, aldehyde and ketone, carboxyl, thiol, and halogen groups are described as well as their application. 

Similar to biochip technology a poly-L-lysine monolayer can be bound via adsorption onto a gold cluster coated with a self-assembled monolayer of a carboxylated thiol e.g. mercapto-succinic acid. Using a biotinylated lysine-polymer proteins are immobilized via avidin conjugation. The poly-L-Iysine monolayer including all the proteins can be rinsed from the surface with a low or high pH buffer. 

The use of trifunctional amino acids, such as lysine, glutamic or aspartic acid, cysteine and serine, in the synthesis of 2,5-morpholinediones, allows the introduction of respectively amine, carboxyl, thiol and hydroxyl functional groups [25-40]. 

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