A-Amino-n-butyric acid

Acetyl-a-amino-n-butyric acid [34271-24-4] M 145.2, pK 3.72. Crystd twice from water (charcoal) and air dried [King and King J Am Chem Soc 78 1089 7956]. 

Malcolm (1973, 1975) reported possible observable differences between the pressure-area curves of poly(L-alanine) mixed with poly(D-a-amino-n-butyric acid) and the corresponding mixture containing poly(D-alanine). Shafer (1974) observed differences in the film pressure between (/ )-phosphatidyl serine with poly-L-lysine and the corresponding film with poly-D-lysine injected under the film. 

We do not know the extent to which the Murchison organics reflect what was available on early Earth before life emerged. The rich inventory of amino acids does not appear to be universal in carbonaceous chondrites (although the number that have been examined in detail is very small). For example, only a few amino acids (glycine, alanine, a-aminoisobutyric acid, a-amino-n-butyric acid, y-aminobutyric acid) are found in the meteorite that fell in 2000 on Tagish Lake, Canada (Table 5.3).7 The near absence of complex amino acids is significant, inasmuch as the meteorite was captured in a pristine condition soon after it fell. 

Poly-DL-a-amino-n-butyric acid CHCb, 90% DCA, 10% +81 Downie et al. (1957)... 

More recently, Henning and Ammon (H19) described 10 aliphatic keto and aldehydic adds in normal urine. In addition to a-ketoglutaric, oxalacetic, pyruvic, glyoxylic, and a-ketoisocaproic acids, they found hydroxypyruvic, a-keto-y-methylthiobutyric, a-keto-fi-hydroxybutyric, a-keto-P-methylvaleric and a-keto-n-butyric acids, that is to say, the keto acids corresponding, respectively, to serine, methionine, threonine, isoleucine, and a-amino-n-butyric acid. They conclude that one finds in normal human urine the keto acids corresponding to all the amino adds normally present in urine, with the exception of those correspond-... 

Itoh et al. (1969) have measured the far-infrared spectra (700 to 60 cm ) of the x-helix structures of poly(L-a-amino-n-butyric acid), poly-L-norvaline, poly-L-nor-leucine, and poly-L-leucine, as well as the spectra of the ) -form structures of poly(L-a-amino-n-butyric acid), poly-L-valine, poly(DL-a-amino-n-butyric acid), poly-DL-norvaline, and poly-DL-norleucine. The a-helix has characteristic bands near 690, 650, 610, 380, 150, and 100cm . The -form has characteristic bands near 700, 240, and 120 cm . The vibrations of the main chain are strongly coupled with the deformation vibrations of the side chains. An earlier study (Itoh et al., 1968) involved various polyalanines and correlations of spectra with a- and j8-structures. 

The adsorptiop of four apliphatic a-amino acids, DL-norleucine (NL), DL-norvaline (NV), DL-a-amino-n-butyric acid (ABA) and DL-a-alanine (AL), at the mercury-neutral aqueous solution interface has been studied by means of double-layer capacitance, potential of zero charge, and surface tension measurements [96]. The adsorption of NL, NV, and ABA obeys the Frumkin isotherm. The interaction parameter and the potential dependence of the adsorption energy were determined [96]. The shifts of p.z.c. with surface coverage are negative for AL and positive for ABA, NV, and NL, which can be explained by assuming the existence of a small dipole component perpendicular to the mercury surface. 

Aminobutyric acid a-Amino-i-butyric acid a-Amino-n-butyric acid y-Aminobutyric acid jS-Amino-i-butyric acid Serine... 

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