Rapid and Quantitative Determination of S-Adenosyl-L-Methionine in the Fermentation Process by Surface-Enhanced Raman Scattering.

Hairui Ren,Xin Zhang,Haijun Xu,Zheng Wang,Zhenglong Wu,Yongmei Zhao,Zhaoyang Chen

doi:10.1155/2016/4910630

Abstract

Concentrations of S-Adenosyl-L-Methionine (SAM) in aqueous solution and fermentation liquids were quantitatively determined by surface-enhanced Raman scattering (SERS) and verified by high-pressure liquid chromatography (HPLC). The Ag nanoparticle/silicon nanowire array substrate was fabricated and employed as an active SERS substrate to indirectly measure the SAM concentration. The linear relationship between the integrated intensity of peak centered at ~2920 cm−1 in SERS spectra and the SAM concentration was established, and the limit of detections of SAM concentrations was analyzed to be ~0.1 g/L. The concentration of SAM in real solution could be predicted by the linear relationship and verified by the HPLC detection method. The relative deviations (δ) of the predicted SAM concentration are less than 13% and the correlation coefficient is 0.9998. Rolling-Circle Filter was utilized to subtract fluorescence background and the optimal results were obtained when the radius of the analyzing circle is 650 cm−1.

Highlights

S-Adenosyl-L-Methionine (SAM) was discovered approximately 60 years ago
In the investigation carried out here, the linear relationship (y = 240.10x + 112.65) between the concentration of SAM and the integrated intensity of peak centered at ∼2920 cm−1 was established
The linear relationship has the same dependence of SAM concentration in aqueous solutions and the real solutions, due to the weak influence on 2920 cm−1 of other contents in biological cells

Summary

Introduction

S-Adenosyl-L-Methionine (SAM) was discovered approximately 60 years ago. Since SAM has been identified with a wide spectrum of biological processes ranging from the synthesis of various neurotransmitters in the brain and catecholamine metabolism to gene expression and cell growth, differentiation, and apoptosis, to establish the “SAM empire” called by Cantoni [1,2,3]. An effective method for detecting SAM is beneficial to the investigation of the major role of SAM in cell function metabolism and the treatment of clinical disorders. The method can be used to optimize the fermentation conditions in fermentation process by monitoring the production of SAM. Sturgess measured SAM content of the commercially available supplements by high-pressure liquid chromatographyUV diode array detection and showed that the percentage of measured SAM was greater than threefold variation compared to the stated amount on the packaging [9]. Han et al used high-pressure liquid chromatography (HPLC) to measure the production of SAM and L-isoleucine with 0.67 g/L and 13.8 g/L in Corynebacterium [10].

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Results

Conclusion