Ile/QVYZY2&1 &&(2S,3S)- or L(+)- Form/H-ILE-OH/L-Ile/N-methyl Ile/H-DL-Ile-OH/a-Amino-b-methylvaleric Acid/L-Ile (2S,3S)/L-Isoleucine/2-Amino-3-methylvaleric acid/DL-2-Amino-3-methylpentanoic acid/L-Isoleucine (JP15)/2-amino-3-methylpentanoic acid/(2S,3S)-a-Amino-b-methyl-n-valeric acid/H-lle-OH/Isoleucin/(2S,3S)-a-Amino-b-methylvaleric acid/Isoleucine/(2S,3S)-2-amino-3-methylpentanoic acid/(2S,3S)-2-Amino-3-methylpentanoicacid/Z-(s,S)-isoleucine/L-Isoleusine/Isoleucine, DL-/H-L-ILE-OH/ISOLEUCINE, L-/ISO-LEUCINE/(S,S)-Isoleucine/(±)-Isoleucine/DL-Isoleucine/Acetic acid, amino-sec-butyl-/(2S,3S)-Ile/Isoleucine, L- (8CI)/(±)-erythro-2-Amino-3-methylpentanoic acid/(S)-isoleucin/L-Isoieucine/(2S,3S)-2-amino-3-methyl-Pentanoic acid/L(+)-Isoleucin
225.8±23.0 °C at 760 mmHg
HS Code Reference
Personal Projective Equipment
For Reference Standard and R&D, Not for Human Use Directly.
provides coniferyl ferulate(CAS#:73-32-5) MSDS, density, melting point, boiling point, structure, formula, molecular weight etc. Articles of coniferyl ferulate are included as well.>> amp version: coniferyl ferulate
Chemical shifts are often the only nuclear magnetic resonance parameter that can be obtained for challenging macromolecular systems. Here we present a framework to derive the conformational sampling of isoleucine side chains from 13C chemical shifts and demonstrate that side-chain conformations in a low-populated folding intermediate can be determined.
Determining isoleucine side-chain rotamer-sampling in proteins from 13C chemical shift.
Siemons L1, Uluca-Yazgi B2, Pritchard RB1, McCarthy S3, Heise H2, Hansen DF1.
2019 Dec 7;
A rational approach that may be applied to a broad class of enzyme-catalyzed reactions to design enzyme inhibitors affords a powerful strategy, facilitating the development of drugs and/or molecular probes of enzyme mechanisms. A strategy for the development of substrate-product analogues (SPAs) as inhibitors of racemases and epimerases is elaborated using isoleucine 2-epimerase from Lactobacillus buchneri (LbIleE) as a model enzyme. LbIleE catalyzes the PLP-dependent, reversible, racemization or epimerization of nonpolar amino acids at the C-2 position. The enzyme plays an important role in the biosynthesis of branched-chain d-amino acids and is a potential target for the development of antimicrobial agents. 3-Ethyl-3-methyl-l-norvaline (Ki = 2.9 ± 0.2 mM) and 3-ethyl-3-methyl-d-norvaline (Ki = 1.5 ± 0.2 mM) were designed as SPAs based on the movement of the sec-butyl side chain of the substrate l-Ile during catalysis, and were competitive inhibitors with binding affinities exceeding that of l-Ile by 1.3- and 2.5-fold, respectively. Surprisingly, these compounds were not substrates, but the corresponding compounds lacking the 3-methyl group were substrates. Unlike serine, glutamate, and proline racemases, which exhibit stringent steric requirements at their active sites, the active site of LbIleE was amenable to binding bulky SPAs. Moreover, LbIleE bound the SPA 2,2-di-n-butylglycine (Ki = 11.0 ± 0.2 mM) as a competitive inhibitor, indicating that the hydrophobic binding pocket at the active site was sufficiently plastic to tolerate gem-dialkyl substitution at the α-carbon of an amino acid. Overall, these results reveal that amino acid racemases/epimerases are amenable to inhibition by SPAs provided that they possess a capacious active site.
Substrate-product analogue inhibitors of isoleucine 2-epimerase from Lactobacillus buchneri by rational design.
Sorbara NT1, MacMillan JWM, McCluskey GD, Bearne SL.
2019 Sep 25
Plasma elevations of the amino acids alloisoleucine and argininosuccinic acid (ASA) are pathognomonic for maple syrup urine disease and argininosuccinate lyase deficiency, respectively. Reliable detection of these biomarkers is typically achieved using methods with tedious sample preparations or long chromatographic separations, and many published amino acid assays report poor specificity and/or sensitivity for one or both of these compounds. This report describes a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) method that provides rapid quantification of alloisoleucine and ASA in human plasma. The basis of this method is a mixed-mode solid phase separation that achieves baseline resolution of alloisoleucine from isobaric interferents without the use of derivatization or ion pairing agents. The inject-to-inject time is 6 min including elution, column washing and re-equilibration. Validation studies demonstrate excellent limits of quantification (1 μmol/L), linearity (r = 0.999 from 1 to 250 μmol/L), accuracy (bias = -3.8% and -10.1%), and inter-assay imprecision (CV < 8.06%) for plasma analyses. Data from long-term clinical application confirms chromatographic consistency equivalent to more traditional reversed-phase or HILIC based columns. Additional matrix studies indicate low suppression (<10%) for a wide range of amino acids and compatibility with other matrixes such as blood spot analyses. Finally, analysis of our first 257 clinical specimens demonstrates high analytic specificity and sensitivity, allowing the detection of subtle but clinically relevant elevations of alloisoleucine and ASA that may be missed by other less sensitive methods. In conclusion, the novel LC-MS/MS method reported here overcomes a number of the challenges associated with alloisoleucine and ASA quantification. Combining this approach with published incomplete amino acid quantification methods allows, for the first time, a rapid and comprehensive LC-MS/MS analysis of underivatized amino acids without the use of ion pairing agents. Copyright © 2019 Elsevier B.V. All rights reserved.
ASA; Amino acid; Argininosuccinic aciduria; Intrada; L-Alloisoleucine; MSUD
Rapid quantification of underivatized alloisoleucine and argininosuccinate using mixed-mode chromatography with tandem mass spectrometry.
Griffin C1, Ammous Z2, Vance GH1, Graham BH1, Miller MJ3.
2019 Oct 1;