A new approach of indirect enzyme-linked immunosorbent assay for determination of D-glutamic acid throughin situconjugation

Abstract

We propose a new approach of an indirect enzyme-linked immunosorbent assay (ELISA) for determination of D-glutamic acid (D-Glu) using a monoclonal antibody against D-glutamic acid (D-Glu-MAb), which recognizes D-Glu-glutaraldehyde (GA) molecule but not D-Glu molecule. Human serum albumin (HSA) was coated on an immunoplate and reacted with D-Glu via GA to produce D-Glu-GA-HSA conjugates in situ in the well to be recognized by D-Glu-MAb, which enabled the development of an indirect ELISA for the determination of free D-Glu. In this indirect ELISA, D-Glu can be specifically detected with limit of detection of 7.81 μ g/mL. Since anti-conjugate antibodies are often produced, even though anti-hapten antibodies are desired, this new approach could be very useful as an application of anti-conjugate antibodies to the development of quantitative analysis for detecting hapten.

Enantioselective Glutamic Acid Discrimination and Nanobiological Imaging by Chiral Fluorescent Silicon Nanoparticles

“…Significantly, gSiNPs synthesized using precursors devoid of l -dopa exhibited no discernible discrimination between l - and d -glutamic acids under identical conditions (Figure S6). Compared with existing reports, ,,,,, this method has high sensitivity, fast response time, and convenient operation procedures (Table ). In addition, the influence of other chiral compounds on the fluorescence intensity of chiral gSiNPs has also been investigated.…”

“…So far, the methods for separating glutamic acid enantiomers mainly included ultrasonic field, MISPE, crystallization separation technology, and CE . In unison, the approaches for detecting glutamic acid enantiomers incorporated fluorometry, − electrochemical, continuous fractional crystallization, ELISA, microbiological assay, ion channel sensors, etc. Among them, the fluorescence method has attracted widespread attention due to its advantages of high sensitivity, fast analysis speed, and noninvasive biological imaging potential.…”

“…However, little is known about the function of D-glutamic acid, although it has been reported to be present in bacterial cell walls, various plants, rat liver, kidney, and brain tissue. 8 Therefore, distinguishing the enantiomers of glutamic acid is of vital importance for the subsequent study of the physiological function of enantiomer pure glutamic acid and may also provide important references for the application of enantiomer pure glutamic acid in the diagnosis and treatment of diseases. Concurrently, the use of the enantiomer pure glutamic acid obtained thereby will effectively avoid the adverse consequences of the racemate on the organism and even the human body and avoid the recurrence of events similar to "thalidomide".…”

“…l -Glutamic acid is a neurotransmitter in the nervous system of vertebrates, which controls cognitive processes in the brain, and is also an essential compound for the citric acid cycle. However, little is known about the function of d -glutamic acid, although it has been reported to be present in bacterial cell walls, various plants, rat liver, kidney, and brain tissue . Therefore, distinguishing the enantiomers of glutamic acid is of vital importance for the subsequent study of the physiological function of enantiomer pure glutamic acid and may also provide important references for the application of enantiomer pure glutamic acid in the diagnosis and treatment of diseases.…”