Epsilon amino groups

In a study being conducted at Case Western Reserve University under the direction of Dr. Lawrence Sayre, trifluoromethyl-substituted analogs of 2,5-hexanedione will be synthesized, compared with the parent compound in chemical model studies, and evaluated for neurotoxicity in rats. This is part of an effort to address how gamma-diketone-induced pyrrole formation at neurofilament-based lysine epsilon-amino groups leads to neurofilament accumulations. Nuclear magnetic resonance (NMR) studies will provide direct visualization of the nature of chemical modification. 

Insulin detemir is a long-acting insulin analogue that lacks threonine at the B30 position and is acylated with a 14-carbon myristoyl fatty acid side-chain at the epsilon-amino group of the lysine in the B28 position. This stimulates binding to albumin and increases the half-life, extending its duration of action. 

Through their lipophilic nature the aldehyde lipid peroxidation products remain associated with the LDL particle, diffuse to the apoB and react there with amino-acid sidechains (for example epsilon amino groups of lysine). 

Improvement in functionality of the major soy globulins can be obtained by structural modification of the proteins. Frequently this is done by chemical modification of the lysine epsilon-amino groups or by alkaline or heat treatment. We have described a procedure for preparation of a superior soy product without alteration of the amino acids (1). 

Preliminary evidence from enzymatic digestion of the native 7S and 11S proteins suggests that the 7S protein may have a more hydrophilic surface than the 11S protein. Thus, trypsin digests the 7S fraction more rapidly than the 11S at pH 5.8-6.7, whereas rennin degrades the 11S more rapidly than the 7S. The epsilon-amino groups of lysine may also be more available on the surface of the 7S resulting in easier succinylation. 

Acetaldehyde may bind to lipids and proteins, principally through the epsilon amino group of lysine, to form unstable acetaldehyde-Schiff base adducts ( adduct , in chemistry a chemical compound that forms from the addition of two or more substances). Although such adducts are unstable and the reaction is readily reversed, further reduction produces a stable Schiff base that is not easily reversed (Figure 7.1). 

Prior to sequencing, all immobilized protein samples were treated with PIC to derivatize the epsilon amino groups of the lysine residues into phenylureas (5). The PVDF membrane was placed in a microcentrifuge tube. Aliquots (3 pL) of 2.5% (v/v) PIC and 2.5% (v/v) diisopropyl ethylamine (DIEA), both in acetonitrile, were applied to the PVDF disk. The membrane was dried by placing the open microcentrifiige tube on a heating block at 60° C. 

The coenzyme form of pyridoxine is known as pyridoxal phosphate (PP) The most common type of reaction requiring PP as a coenz5mie is transamination. Enzymes catalysing such reactions are known as transaminases or aminotransferases. The coenzyme binds to its apoenzyme via Schiff s base between its aldehyde group and the epsilon amino group of a lysine in the... 

The important function of biotin is its role as coenzyme for carboxylase, which catalyses carbon dioxide fixation or carboxylation reaction. The epsilon amino group of lysine in carboxylase enzymes combines with the carboxyl group of biotin to form covalently linked biotinyl carboxyl carrier protein (BCCP or biocytin) (Figure 6.8). This serves as an intermediate carrier of carbon dioxide. The carboxylation of acetyl CoA to malonyl CoA in presence of acetyl CoA carboxylase requires biotin as coenzyme. Propionyl carboxylase and pyruvate carboxylase are also associated with biotin. 

The coenzyme form of pantothenic acid is coenzyme A and is represented as CoASH. The thiol group acts as a carrier of acyl group. It is an important coenzyme involved in fatty acid oxidation, pyruvate oxidation and is also biosynthesis of terpenes. The epsilon amino group of lysine in carboxylase enzymes combines with the carboxyl carrier protein (BCCP or biocytin) and serve as an intermediate carrier of C02. Acetyl CoA pyruvate and propionyl carboxylayse require the participation of BCCP. The coenzyme form of folic acid is tetrahydro folic acid. It is associated with one carbon metabolism. The oxidised and reduced forms of lipoic acid function as coenzyme in pyruvate and a-ketoglutarate dehydrogenase complexes. The 5-deoxy adenosyl and methyl cobalamins function as coenzyme forms of vitamin B12. Methyl cobalamin is involved in the conversion of homocysteine to methionine. 

Pyridoxal phosphate is covalently attached to the amino transferases via a Schiff s base linkage formed between the aldehyde group of pyridoxal phosphate and the epsilon amino group of lysine residue of the enzyme. Pyridoxal phosphate is converted to pyridoxamine phosphate. In the second stage, the amino group attached to pyridoxamine phosphate is transferred to a different keto acid to yield a new amino acid and releases pyridoxal phosphate... 

Histidine is frequently involved in the co-ordination of metal ions, and is thus a target for metal-catalysed oxidation [95], generating 2-oxo-histidine and its ring-ruptured products. It has also been postulated that the formation of Schiff bases between newly formed carbonyl moieties and epsilon amino groups on lysine residues may account for protein aggregation. 

All four carboxylases use bicarbonate as their one-carbon substrate and, in all, the biotin is covalently linked by an amide bond between the carboxyl of biotin and an epsilon amino group of a lysyl residue in the holocarboxylase synthase (= biotin ligase) that catalyzes the formation of the covalent bond. Biotinylation of histones is involved in regulation of gene transcription and may also play a role in packaging of deoxyribonucleic acid (DNA). Biotin has also been found to inhibit the generation of reactive oxygen species (ROS) by neutrophils in vitro. 

UK insulin determir insulin Levemir Recombinant human insulin with acylated lysines formed by acylation of epsilon amino groups of specific Lys resi dues Diabetes... 

Fig. 8.21. Aldolases catalyze carbon-carbon cleavage in reactions that are usually reversible. In glycolysis, the enzyme fructose 1,6-bisphosphate aldolase cleaves a carbon-carbon bond in fructose 1,6-bisphosphate. Aldolases have a lysine epsilon amino group in the active site that participates in the reaction.

C. Candide, J.P. Reyftmann, R. Santus, J.C. Maziere, P. Morliere, S. Goldstein (1988). Modification of epsilon-amino group of lysines, cholesterol oxidation and oxidized lipid-apoprotein cross-link formation by porphyrin-photosensitized oxidation of human low density lipoproteins. Photochem. PhotobioL, 48, 137-146. 

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