Description_x000D_ General description_x000D_ Sarcosine, also known as N-methylglycine, is an amino acid that participates in one-carbon metabolism, serving as a one-carbon donor in mitochondrial reactions. Elevated levels of sarcosine may indicate deficiencies in Vitamin B12 and/or folate. Sarcosine is also an intermediate in glycine and choline metabolism. In the brain, sarcosine acts as an inhibitor of the type I glycine transporter, resulting in increased glycine levels and NMDA receptor activation suggesting it may be a therapeutic agent for the treatment of some mental illnesses such as schizophrenia, depression, or obsessive compulsive disorder._x000D_ Suitability_x000D_ This kit is suitable for sarcosine detection in cell and tissue culture supernatants, plasma, serum, and other biological samples. Urine samples are not suitable for use with this assay because of sample interferences._x000D_ Principle_x000D_ In this assay, sarcosine concentration is determined by a coupled enzyme reaction, which results in a colorimetric (570 nm)/fluorometric (λex = 535/λem = 587 nm) product, proportional to the sarcosine present.