287484-39-3Relevant articles and documents
N,N-Dimethyl leucines as novel Isobaric tandem mass tags for quantitative proteomics and peptidomics
Xiang, Feng,Ye, Hui,Chen, Ruibing,Fu, Qiang,Li, Ngjun
, p. 2817 - 2825 (2010)
Herein, we describe the development and application of a set of novel N,N-dimethyl leucine (DiLeu) 4-plex isobaric tandem mass (MS2) tagging reagents with high quantitation efficacy and greatly reduced cost for neuropeptide and protein analysis. DiLeu reagents serve as attractive alternatives for isobaric tags for relative and absolute quantitation (iTRAQ) and tandem mass tags (TMTs) due to their synthetic simplicity, labeling efficiency, and improved fragmentation efficiency. DiLeu reagent resembles the general structure of a tandem mass tag in that it contains an amine reactive group (triazine ester) targeting the N-terminus and ε-amino group of the lysine side chain of a peptide, a balance group, and a reporter group. A mass shift of 145.1 Da is observed for each incorporated label. Intense a1 reporter ions at m/z 115.1, 116.1, 117.1, and 118.1 are observed for all pooled samples upon MS2. All labeling reagents are readily synthesized from commercially available chemicals with greatly reduced cost Labels 117 and 118 can be synthesized in one step and labels 115 and 116 can be synthesized in two steps. Both DiLeu and iTRAQ reagents show comparable protein sequence coverage (～43%) and quantitation accuracy ( a marine model organism, Callinectes sapidus.
Differential isotope-labeling for Leu and Val residues in a protein by E. coli cellular expression using stereo-specifically methyl labeled amino acids
Miyanoiri, Yohei,Takeda, Mitsuhiro,Okuma, Kosuke,Ono, Akira M.,Terauchi, Tsutomu,Kainosho, Masatsune
, p. 237 - 249 (2013)
The 1H-13C HMQC signals of the 13CH 3 moieties of Ile, Leu, and Val residues, in an otherwise deuterated background, exhibit narrow line-widths, and thus are useful for investigating the structures and dynamics of larger proteins. This approach, named methyl TROSY, is economical as compared to laborious methods using chemically synthesized site- and stereo-specifically isotope-labeled amino acids, such as stereo-array isotope labeling amino acids, since moderately priced, commercially available isotope-labeled α-keto acid precursors can be used to prepare the necessary protein samples. The Ile δ1-methyls can be selectively labeled, using isotope-labeled α-ketobutyrates as precursors. However, it is still difficult to prepare a residue-selectively Leu and Val labeled protein, since these residues share a common biosynthetic intermediate, α-ketoisovalerate. Another hindering drawback in using the α-ketoisovalerate precursor is the lack of stereo-selectivity for Leu and Val methyls. Here we present a differential labeling method for Leu and Val residues, using four kinds of stereo-specifically 13CH 3-labeled [U-2H;15N]-leucine and -valine, which can be efficiently incorporated into a protein using Escherichia coli cellular expression. The method allows the differential labeling of Leu and Val residues with any combination of stereo-specifically isotope-labeled prochiral methyls. Since relatively small amounts of labeled leucine and valine are required to prepare the NMR samples; i.e., 2 and 10 mg/100 mL of culture for leucine and valine, respectively, with sufficient isotope incorporation efficiency, this approach will be a good alternative to the precursor methods. The feasibility of the method is demonstrated for 82 kDa malate synthase G.
Stereoselective synthesis of L-[15N] amino acids with glucose dehydrogenase and galactose mutarotase as NADH regenerating system
Chiriac, Maria,Lupan, Iulia,Bucurenci,Popescu,Palibroda
, p. 171 - 174 (2008/09/19)
We have developed an efficient stereospecific enzymatic synthesis of L-[15N]-valine, L-[15N]-leucine, L-[15N]- norvaline, L-[15N]-norleucine and L-[15N]-isoleucine from the corresponding α-keto acids by coupling the reactions catalysed by leucine dehydrogenase and glucose dehydrogenase/galactose mutarotase. Giving high yields of L-amino acids, the procedure is economical and easy to perform and to monitor at a synthetically useful scale (1-10 g). Copyright
