Sakaguchi Test- Definition, Principle, Procedure, Result, Uses


Amino acids are the building blocks of proteins, and they have different chemical properties that can be used to identify and characterize them. One of the methods to detect amino acids is by performing color reactions or tests that produce a specific color when a certain amino acid is present. These tests are based on the reaction of specific functional groups in the amino acid with certain reagents.

One of the color reactions that is used to detect arginine, an amino acid with a guanidinium group, is the Sakaguchi test. The Sakaguchi test is a biochemical test that was discovered by and named after Shoyo Sakaguchi, a Japanese food scientist, in 1925. The test consists of a colorimetric reaction between 1-naphthol and the guanidinium group of arginine, in the presence of an oxidizing agent. The test produces a red-colored complex that indicates the presence of arginine in either free or protein-bound form.

The Sakaguchi test is a simple and specific test for arginine, but it has some limitations as well. The test is qualitative and not quantitative, as the rate of color development is slow and some guanidinium groups might be destroyed by the reagent. The test also requires strong alkaline conditions and an oxidizing agent that might interfere with other compounds in the sample.

In this article, we will discuss the definition, objective, principle, requirements, procedure, result, interpretation, uses and limitations of the Sakaguchi test in detail. We will also provide some examples of applications of the Sakaguchi test in different fields.