Amino acids N-methyl

Salts with the amino acids N-methyl-stearoylglycine65 and glutamic acid66, and the vitamins ascorbic acid65 and nicotinic acid65 have also been evaluated. 

N-derivatized a-amino acids N-methyl tert-butyl carbamoylated quinine Methanol—O.IM 203 ammonium acetate, pH 6.0 (80 20)... 

The main genera responsible for freshwater toxic blooms are Microcystis, Anabaena, Aphanizomenon and Oscillatoria. Toxins produced include 1. anatoxins, alkaloids and peptides of Anabaena 2. the peptide microcystin and related peptides of Microcystis 3. aphantoxins, compounds of Aphanizomenon with properties similar to some paralytic shellfish poisons. Properties of Oscillatoria toxin suggest they are peptides similar to those of Microcystis. Microcystis toxins are peptides (M.W. approx. 1200) which contain three invariant D-amino acids, alanine, erythro-3-methyl aspartic and glutamic acids, two variant L-amino acids, N-methyl dehydro alanine and a 3-amino acid. Individual toxic strains have one or more multiples of this peptide toxin. The one anatoxin characterized is a bicylic secondary amine called anatoxin-a (M.W. 165). The aphantoxin isolated in our laboratory contains two main toxic fractions. On TLC and HPLC the fractions have the same characteristics as saxitoxin and neosaxitoxin. 

The cosmopolitan cyanobacterium Microcystis aeruginosa is frequently the major component of freshwater cyanobacterial blooms. These blooms can cause serious water management problems and are occasionally associated with animal poisoning. The aeruginosa toxins are potent lethal peptides which contain three invariant D-amino acids (Ala, erythro-3-methyl Asp, and Glu), two variant L-amino acids, N-methyl dehydroalanine, and a 3 amino acid (1-3). Multiple toxins have been purified from clonal isolates (1,4). The toxic peptide described in this chapter is denoted toxin-LR using the standard one-letter abbreviations for its two variant amino acids, leucine and arginine. 

Bisebromoamide is cytotoxic linear peptide isolated from the marine cyanobacterium Lyngbya sp. (Teruya et al., 2009). Structure of bisebromoamide contains rich unusual amino acid derivatives with D-amino acids, N-methylated amino acids, a brominated tyrosine, a modified 4-methylpro-line, a 2-substituted thiazoline-4-methyl-4-carboxylic acid unit, and a rare... 

Figure 1. Structure of the blue-green algal toxin microcystin-LR. Besides the two variable L-amino acids, leucine and arginine, the microcystin contains three D-amino acids (glutamic acid, alanine and methylaspartic acid) and two unusual amino acids, N-methyl-dehydroalanine (Mdha) and 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid (Adda) (see Ref. 4).

Microcystins (Figure lA) are cyclic heptapeptides of low molecular weight quite frequently implicated in intoxication events and synthesized by the cyanobacteria genera such as Microcystis, Anabaena, Planktothrix, and Nostoc. They contain two unusual amino-acids N-methyl-dehydroalanine (Mdha) and 3-amino-9-met-hoxy-2,6,8-trimethyl-10-phenyl-4,6-dienoic add (ADDA). The most common sequence is o-Ala -L-X -o-Masp -L-Z" -Adda -D-Glu -Mdha, where Masp stands for methylaspartic acid and X and Z for two variable... 

V -Methyl-L-2,3-diaminopropionic acid (66) (Fig. 13.13) is found in plants of the genus Cycas, Cycadaceae, a gymno-spermous family. Several of these plants are used as human food sources in Oceania, whereas others are eaten by animals in the South Pacific and in Australia. A form of amyotrophic lateral sclerosis (ALS or Lou Gehrig s disease) used to be endemic among the Chamorros of Guam. An unusual amino acid N -methyl-L-amino-2,3-diaminopropionic acid (N -methylamino-L-alanine) (66), found in Cycas species. 

The condensation reaction of an imine derived from an aldehyde with ethyl bromoacetate under Reformatsky53 conditions led to a mixture of amino-esters and P-lactams. When acetaldehyde was condensed with methylamine, Schiff base 4.116 was the product A Reformatsky reaction with ethyl bromoacetate gave a mixture of the P-lactam (4.117) and the amino-ester (4.118). Acid hydrolysis and hydrogenation led to the P-amino acid N-methyl-3-aminobutanoic acid (4.119). When benz-aldehyde was the aldehyde starting material, 3-(N-methylamino)-3-phenylpropanoic acid (4.120) was the final product. ... 

They are modified or "interrupted" soaps that possess many of the more desirable properties of synthetic surfactants. VANSEAL surfactants are derived from natural fatty acids and the amino acid, N-methyl glycine (Sarcosine). They are available commercially in the acid form or as the sodium salt. 

In this chapter, the results of study of extraction properties of two new liquid extraction agents—methyl phosphorylated derivative natural amino acids— N-methyl aminoacetic acid—sarcosine (1) and -alanine (2) in processes of liqtrid extraction of a mrmber of metals iorrs (Table 11.1) are provided. The potential eoordination centers in used reagents are marked by asterisk. 

Pompanopeptin B is a pentapeptide isolated from Lyng-bya confervoides harvested in Florida (Pompano Beach), which contains a new amino acid, N-methyl-2-amino-6-(4 -hydroxyphenyl)-hexanoic acid (N-Me-Ahpha) (Matthew et al, 2008b). 

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