Sullivan and McCarthy’s Test- Definition, Principle, Procedure, Result, Uses


Methionine is one of the essential amino acids that humans cannot synthesize and must obtain from their diet. Methionine plays a vital role in various biological processes, such as protein synthesis, methylation, and sulfur metabolism. Methionine is also a precursor of other important molecules, such as cysteine, taurine, and S-adenosylmethionine. Therefore, the detection and quantification of methionine in biological samples is of great interest for biochemical and clinical studies.

Sullivan and McCarthy’s test is a simple and rapid method for the detection of methionine or methionine-containing proteins. The test is based on the formation of a red-colored complex between nitroprusside and methionine under alkaline conditions and subsequent acidification. The test has a high specificity for methionine as it does not react with other sulfur-containing amino acids like cysteine and cystine. The test can be performed with minimal equipment and reagents and can be applied to various types of samples, such as urine, blood, serum, tissue extracts, and fermented products.

In this article, we will discuss the definition, principle, procedure, result, uses, and limitations of Sullivan and McCarthy’s test. We will also provide some examples of how this test can be used in different contexts and applications. By the end of this article, you will have a clear understanding of what Sullivan and McCarthy’s test is and how it works.