Lysine carboxymethyl derivative

Haloacetates. In alkaline solution lysine residues can be alkylated in the presence of iodo- or bromoacetate ions (118). Both mono- and di-carboxymethyl derivatives can be formed. Some of the characterized derivatives are listed at the end of Table VI. Number 25, t-CM-Lys-41-RNase, shows a very low activity when measured by a step 2 assay employing C > p as substrate. This same compound is active in the depolymerization of 5S RNA (119) but the evidence presented to show that it is not the result of contamination with native RNase-A can be interpreted to suggest the opposite. 

Radioimmunoassay methods have been developed for pentazocine which were shown to be both sensitive and specific. An early method utilized tritium labeled pentazocine at 1.5 Ci/mmol. Antibodies were produced in rabbits to both an azoben-zoic acid and a carboxymethyl derivative of pentazocine coupled by carbodiimide condensation to poly-L-lysine. No cross reactivity was found for metabolites and benzomorphan analogs to the former antiserum with only conjugated pentazocine crossreacting with the latter antiserum (62). 

As already pointed out, the chief advantage of using derivatives of haloacetates as modification reagents is that the carboxymethyl derivatives of most of the nucleophilic amino acids have been described. The chromatographic behavior of the carboxymethylated derivatives of lysine, cysteine and histidine have been described in ch. 2. O-Carboxymethyl tyrosine appears as a single peak in the long column... 

Various modification products have been isolated by chromatography on Amberlite CG-50 of a mixture of A-carboxymethylated derivatives of lysozyme. In each carboxymethyl derivative the position of the modified amino-acid was established. It was found that L-histidine-15, L-lysines-1, -33, -96, or -97 are blocked, whereas L-lysines-13 and -116 remain unaffected. Possible causes of this selectivity were discussed. Salt activation of carboxy-methyl derivatives of lysozyme proceeds more readily the higher the degree of modification, and the enzymatic activity of carboxymethyl derivatives of lysozyme is higher than that of the native enzyme owing to their increased affinity for substrate (chitin). 

Other Alkyl and Aryl Ethers. - The preparation of selectively 0-alkylated saccharides, including benzyl, allyl, triphenylmethyl, and arylalkyl ethers has been reviewed. Analogues of lipids A and X incorporating 3-O-alkyl (rather than acyl) linkages have been described, and some carbohydrate monoalcohol derivatives have been alkylated with haloacetic acid ester derivatives. ° 3-C -Carboxymethyl D-glucose and D-fhictose compounds have been coupled via the carboxylic acid group to L-lysine in a search for acrosin inhibitors."... 

Thermal treatment during the production and processing of foods leads to a variety of desired changes in color, taste and aroma but also enhances the formation of Advanced Glycation End Products (AGE), formed by the reaction of amino acids and reducing carbohydrates. Carboxymethyl-lysine (CML), a lysine derivative and major AGE, has been detected in dairy products and in a multitude of other foods Various studies indicate that food derived AGEs are absorbed in the intestines with the transephitelial uptake based on passive diffusion... 

---