Amino sarcosine

Almost all actinomycins have the same chromophore, a planar phenoxa2inone dicarboxyUc acid called actinocin. In dactinomycin, the stmcture of which is shown in Figure 12, the two pendent pentapeptide lactones are identical, but in other actinomycins these lactones may be different. In other actinomycins the first amino acid, amide linked with actinocin, is usually L-threonine, as in dactinomycin the second position is sometimes D-aHo-isoleucine instead of D-valine the third position may be sarcosine or oxoproline the fourth position is sarcosine and the fifth position is sometimes /V-methyl isoleucine instead of /V-methylvaline. The lactone ring is always present. 

Amino-4,6-dimethyl-3-oxo-3//-phenoxazine-l,9-dicarboxylic acid also named actinocin is the chromophor of the red antineoplastic chromopeptide aetinomyein D (formula A). Two cyclopenta-peptide lactone rings (amino acids L-threonine, D-valine, L-proline, sarcosine, and 7V-methyl-L-valine) are attached to the carboxy carbons of actinocin by two amide bonds involving the amino groups of threonine. 

Ornithine, proline, hydroxyproline, pipecolic acid and sarcosine yield red zones, glycine greenish-brown and the other amino acids weakly brown ones [3]. The colors of the zones are different if an alcoholic solution of potassium carbonate is used for basification instead of dipping solution II. 

Sodium lauryl sarcosinate is very similar to the lauryl sulfate class of detergents and surfactants. The sulfate group is replaced with the amino acid sarcosinic acid, and the ammonium group is replaced with a sodium atom. The result is a detergent that is milder on the skin and oral membranes, and can be used in toothpastes without causing irritation of the gums. 

With other amino acids, notably glycine and sarcosine, it is necessary to reflux the reactants 1-6 hours. 

The interaction with both synthetic and naturally occurring amino acids has been studied extensively glycine (138, 173, 219-221), a-(173, 219) and /3-alanine (138, 220), sarcosine (219), serine (222), aspartic acid (138, 173, 222-226), asparagine (222), threonine (222), proline (219), hydroxyproline (219), glutamic acid (138, 222-225), glutamine (222), valine (219, 227), norvaline (219), methionine (222, 226), histidine (228, 229), isoleucine (219), leucine (219, 230), norleu-cine (219), lysine (222), arginine (222), histidine methyl ester (228), phenylalanine (138, 222), tyrosine (222), 2-amino-3-(3,4-dihydroxy-phenyl jpropanoic acid (DOPA) (222), tryptophan (222), aminoiso-butyric acid (219), 2-aminobutyric acid (219,231), citrulline (222), and ornithine (222). 

Table 12.1 summarizes the selenoenzymes isolated from Clostridia, which fall into three major categories. The first group is the amino acid reductases, such as GR, sarcosine reductase (SR), betaine reductase (BR), and proline reductase (PR). The second class of selenoenzymes includes FDH. Although a number of clostridial species are suspected to contain a... 

Eubacterium acidaminophilum not only reductively deaminates glycine to ammonia and acetate but also expresses enzymes capable of reductively deaminating sarcosine and betaine when cells are cultured in the presence of formate (Hormann and Andreesen 1989). One would expect that the enzymes catalyzing the latter two reactions might be similar to GR. In fact, the substrate-specific protein B for sarcosine reductase was purified and found to be similar to GR protein B from C. sticklandii (Meyer et al. 1995). Apparently, this organism has evolved means to use different amino acids as electron acceptors and preferentially expresses each in response to conditions in the environment. 

In addition to the 20 amino acids described, there are also a few amino acids quite frequently encountered that are not encoded by DNA. These are mainly found in peptides, and are typically slightly modified versions of the common amino acids, such as N-methyl amino acids. These components are represented by an appropriate variation of the normal abbreviation, e.g. N-methyl amino acids such as Tyr(Me) or Leu(Me), though A-methylglycine is often referred to as sarcosine (Sar). 

Using derivatized glycine usually lowers the yields compared with sarcosin -nevertheless various functionalized glycine derivatives have been used. Amine 245, obtained by reaction of a trimethoxy-indole functionalized amino acid with an aliphatic co-amino-aldehyde, has been coupled with an oligonucleotide to increase the affinity of Cjq conjugates to certain nucleic acids (Figure 4.13) [288]. 

Ring-opening copolymerization was simultaneously investigated with homopolymerization of N-carboxy-a-amino acid anhydrides, NCAs, by Bamford at al Polymerization of a mixture of NCAs of y-ethyl-L-glutamate and sarcosine ... 

The earliest report on such lactim ether formation was from Sammes [72JCS(P1)2494], who converted piperazine-2,5-dione to 2,5-diethoxy-3,6-dihydropyrazine (173) with an excess of triethyloxonium fluoroborate. Subsequently, Rajappa and Advani (73T1299) converted proline-based piperazine-2,5-diones into the corresponding monolactim ethers. The starting material was a piperazinedione in which one of the amino acid units was the secondary amino acid proline, and the other a primary amino acid. This naturally led to the regiospecific formation of a monolactim ether (169) (on O-alkylation) from the secondary amide, whereas the tertiary amide remained intact. This was later extended to piperazine-2,5-diones in which the secondary amino acid was sarcosine [74JCS(P 1)2122], leading to the monolactim ethers (170). 

Secondary amino acids such as sarcosine have some color development with ninhydrin, but its sensitivity is considerably less than that of the primary amino acids. 

The intra-assay variation for plasma was performed in a tenfold analysis and gave CVs of 0.8-4.1% with the exception of tryptophan, methionine, and the imino acids (6.7-8.9%). Urine behaved similarly to plasma in the sense of reproducibility, with CVs between 3.6 and 8.6% in 23 analyses over a 6-month period. Exceptions in this respect were the amino acids with a low ninhydrin color yield, such as / -alanine and sarcosine. 

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