Determination of the Absolute Configuration of α-Amino Acids and Small Peptides by Chiroptical Means

Toome, V.; Weigele, Manfred

doi:10.1016/b978-0-12-304204-0.50010-5

Cited by 5 publications

(3 citation statements)

References 305 publications

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“…All aliphatic (S')-amino acids display a strong positive Cotton effect in the far ultraviolet. This absorption, which is centered near 203 nm when the amino acid is in its zwitterionic form, has generally been attributed to an n-to-* transition of the -carboxylate group (Toome & Weigele, 1981). While the far ultraviolet is generally inaccessible with ordinary polarimeters, modern CD spectrometers can be used to monitor the circular dichroism at wavelengths as low as 190 nm.…”

Section: Mmvvacntataaalpalqmentioning

confidence: 99%

Purification, cloning, and cofactor independence of glutamate racemase from Lactobacillus

Gallo

Knowles²

1993

Biochemistry

112

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Glutamate racemase has been purified more than 12,000-fold from Lactobacillus fermenti. The racemase gene has been cloned using standard hybridization techniques combined with a novel selection for in vivo glutamate racemase activity, and the racemase has been expressed in Escherichia coli as 20-25% of the total soluble cell protein. The cloned gene product is indistinguishable from that purified from Lactobacillus and is a monomer of M(r) 28,300. Both a coupled enzymatic assay and a circular dichroism assay show that the enzyme follows Michaelis-Menten kinetics, with a Km of 0.3 mM and a kcat of 70 s-1 in each reaction direction. Investigations into the cofactor dependence of glutamate racemase indicate that the enzyme employs neither pyridoxal phosphate nor a pyruvoyl group in the labilization of the proton at the stereogenic center of glutamate. Furthermore, the racemase activity is unaffected by the presence of the metal-chelating reagent EDTA. The gene sequence of the racemase is 24% identical to that of aspartate racemase from Streptococcus thermophilus and 30% identical to that of an unidentified open reading frame in the rrnB ribosomal RNA operon of E. coli. Because the two cysteine residues in glutamate racemase and their surrounding regions are well-conserved in both of these sequences, and since glutamate racemase is stabilized by the presence of reduced thiols, these residues are possible candidates for the enzymic bases that deprotonate glutamate at C-2.

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Section: Mmvvacntataaalpalqmentioning

confidence: 99%

Purification, cloning, and cofactor independence of glutamate racemase from Lactobacillus

Gallo

Knowles²

1993

Biochemistry

112

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“…)-61a showing a bisignate CD curve (Figure 9), interpreted in terms of vibronic coupling (section IVA). 33 For the thujylamines (63) and the isothujylamines (64), the interpretation of the CD spectra of their N- e May be due to the n -+ ir* transition of the azomethine group, t Ellipticity measurements not of quantitative significance.…”

Section: (3-amino Alcoholsmentioning

confidence: 99%

The salicylidenamino chirality rule: a method for the establishment of the absolute configurations of chiral primary amines by circular dichroism

Smith¹

1983

Chem. Rev.

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“…At this wavelength the specific rotation is expected to be strongly dependent on the lowest allowed electronic excitation. Historically, this transition has been identified as the n to π* transition of the carboxylate functional group that is present in all of the free amino acids …”

Section: Introductionmentioning

confidence: 99%

Time Dependent Density Functional Theory Modeling of Specific Rotation and Optical Rotatory Dispersion of the Aromatic Amino Acids in Solution

Kundrat

Autschbach

2006

J. Phys. Chem. A

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Time Dependent Density Functional Theory (TDDFT) along with the COnductor-like Screening MOdel (COSMO) has been applied to model the specific rotation at 589.3 nm and the optical rotatory dispersion (ORD) of the aromatic amino acids phenylalanine, tyrosine, histidine, and tryptophan. Solution structures at low, neutral, and high pH were determined. Both the anomalous dispersion absorbing (resonance) region and the lower energy (transparent) region of the ORD of the compounds were modeled. Linear response calculation of the specific rotation and ORD as well as Kramers-Kronig transformations of calculated circular dichroism spectra to model resonant ORD were compared with experimental data from the literature.

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Determination of the Absolute Configuration of α-Amino Acids and Small Peptides by Chiroptical Means

Cited by 5 publications

References 305 publications

Purification, cloning, and cofactor independence of glutamate racemase from Lactobacillus

Purification, cloning, and cofactor independence of glutamate racemase from Lactobacillus

The salicylidenamino chirality rule: a method for the establishment of the absolute configurations of chiral primary amines by circular dichroism

Time Dependent Density Functional Theory Modeling of Specific Rotation and Optical Rotatory Dispersion of the Aromatic Amino Acids in Solution

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