Home
Resources
Publications
Derivatize, Racemize, and Analyze-an Easy and Simple Procedure for Chiral Amino Acid Standard Preparation for Enantioselective Metabolomics

Derivatize, Racemize, and Analyze-an Easy and Simple Procedure for Chiral Amino Acid Standard Preparation for Enantioselective Metabolomics

Jeannie Horak, Michael Lämmerhofer

Anal Chem. 2019 Jun 18;91(12):7679-7689.

PMID: 31083928

Abstract:

A simple, controllable, and reproducible stereoisomerization (racemization and epimerization) protocol for the preparation of scalemic α-amino acid mixtures from stereoisomerically pure standards was developed. Simply derivatize your amino acids with a racemization tag that incorporates a urea bond on the N-terminus of the target amino acid and incubate at elevated temperatures up to 95 °C for defined time periods until the targeted d-amino acid levels are obtained. The racemization tags investigated were 6-aminoquinolyl- N-hydroxysuccinimidyl carbamate (AQC), aminophenyl- N-hydroxysuccinimidyl carbamate (AC), and 3-aminopyridyl- N-hydroxysuccinimidyl carbamate (APC). Employing this method, it was possible to create a ready-to-use, tailor-made chiral uniformly 13C and 15N labeled [U -13C15N]-amino acid standard with the desired d-amino acid percentage within minutes or hours without sample cleanup. A racemization time of 30 min at 95 °C will lead to a d-amino acid level of 1-5%, while 6 h at 95 °C provides 15-30% d-amino acids. Racemization occurs due to imine formation at the chiral carbon atom bound to the urea-linking group without decomposition of labile amino acids such as Asn, Gln, Trp, Cit, and theanine. For amino acids possessing two chiral centers such as dl-Ile or dl-Thr, only the epimerization of isomers with different stereochemistry at the second chiral center will produce all four possible isobaric enantiomers. All measurements were performed on the zwitterionic Chiralpak ZWIX(+) column using a dual hydro-organic flow gradient combined with HPLC-ESI-QTOF-MS analysis. This new racemization method solves the problem of (enantioselective) matrix effects and inaccurate results in LC-MS based enantioselective metabolomics and warrants full MS-compatibility.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
CS38118	Amino Acid Standard			Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: