N-Methyl-L-alanine

This enzyme [EC 1.4.1.17] catalyzes the reaction of N-methyl-L-alanine with NADP and water to produce pyruvate, methylamine, and NADPH. 

METHYLADENINE-DNA GLYCOSYLASE 3-METHYLADENINE-DNA GLYCOSYLASE N-Methyl-L-alanine,... 

Fig.2 The calculated 13C chemical shift map of the Cp carbon in N-acetyl-N -methyl-L-alanine amide obtaining using the FPT INDO method. The chemical shifts were calculated at 15° intervals for the dihedral angles(< >,i /).

The NMR shieldings are calculated by ab initio GIAO-CHF method with the 6-31G basis set. N-acetyl-N -methyl-L-alanine amide (Ac-L-Ala-NH-Me)... 

Figure 1. Structure of N-acetyl-N -methyl-L-alanine amide used in NMR shielding calculations.

A polymer related to poly-L-proline, in the sense that the amide nitrogen is substituted and, therefore, cannot take part in hydrogen bonding, is poly-N-methyl-L-alanine. Conformational energy calculations for this... 

Supporting evidence for this proposal was obtained from amino acid analyses which demonstrated that glycine was the only typical or non N-methylated amino acid present in 4ab and Sab. Marfey analysis of the acid hydrolysates of 4ab, Sab and majusculamide C (6) confirmed that 4ab and Sab differed from majusculamide C (6) in possessing an N-methyl-L-alanine residue rather than an L-alanine residue. Moreover, 4ab and Sab contained an N-methyl-L-leucine residue rather than an N-methyl-L-isoleucine residue,... 

All four five-membered proline ring constraints in the CTP are, however, essential for stabilizing any m-amide-bond conformers (132). A single substitution of N-methyl-L-alanine, or the six-membered homolog, L-pipecolic acid, destabilizes all the cm-amide conformers of c[Pro-pro-Pro-pro] and only the all-trans-amide tttt conformers were populated (see Fig. 9). 

Wilson and Martin (1971) studied Cu(II) complexes with iV-methyl-L-amino acids (and dipeptides) and found four CD extrema in the visible region at 510, 560, 656, and 784 nm for the 2 1 N-methyl-L-alanine complex. Only one Cotton effect occurs above 700 nm and not two as claimed previously (Yasui, 1965 Yasui et al, 1965). A negative sign is observed for the main Cotton effect in the 656-600-nm region for the l configuration. Again, a hexadecant rule appears to provide the simplest general description of the results. 

Janolusimide is a tripeptide isolated from Janolus cris-tatus harvested in the Bay of Naples. This derivative is particularly unusual because it is made up of three rare or original amino adds N-methyl-L-alanine, 4-amino-3-hydroxy-2-methylvaleric acid, and a pyrroHdine-dione tri-substituted with an isopropyl group and two geminated methyl groups (Sodano and Spinella, 1986). Janolusimide is neurotoxic to the mouse, with an LD50 of 5 mgkg . Its possible biosynthesis from alanine, propionate and isobutyrate has been proposed. 

Treatment of N-benzoyl-L-alanine with oxalyl chloride, followed by methanolic triethylamine, yields methyl 4-methyl-2-phenyloxazole-5-carboxylate 32 <95CC2335>. a-Keto imidoyl chlorides, obtained from acyl chlorides and ethyl isocyanoacetate, cyclise to 5-ethoxyoxazoles by the action of triethylamine (e.g.. Scheme 8) <96SC1149>. The azetidinone 33 is converted into the oxazole 34 when heated with sodium azide and titanium chloride in acetonitrile <95JHC1409>. Another unusual reaction is the cyclisation of compound 35 to the oxazole 36 on sequential treatment with trifluoroacetic anhydride and methanol <95JFC(75)221>. 

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. 

C11H12CIN04 N-(2-chloroacetyl)-L-tyrosine 1145-56-8 25.00 1.3161 2 21990 C11H13N03 N-benzoyl-L-alanine methyl ester 7244-67-9 25.00 1.1676 2... 

L-proline NCA is comparatively reactive. In part this may arise from strain in the molecule. However, the fused rings confer a saucer-like shape on the molecule and attack at C5 from the convex side should be relatively free from obstruction by substituents on the ring nitrogen and C4. This is probably the explanation of the comparatively fast reaction of L-proline NCA with Al-isopropylglycine dimethylamide (R4 = iPr), of which the rate coefficient is approximately 6000 times that of the corresponding reaction with N-methyl-DL-alanine NCA (R, = R3 = Me, R2 = H). 

The cyclic 11-peptide contains mainly normal amino acids, one D-alanine and one L-a-aminobutyric acid, but, strikingly, not less than seven iV-methyl groups and a quite uncommon amino acid, a C9-compound (4R)-4[(F)-2-butenyl]-4-methyl-N-methyl-L-threonine. 

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. 

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