What is Sakaguchi reaction?

What is Sakaguchi reaction?

The Sakaguchi reaction is a colorimetric reaction for identification and quantitation of guanidino groups, involving reaction with naphthol and sodium hypochlorite, providing a qualitative test for arginine that is free or in protein (10). This reaction was used by Fogg to show that heterocysts contain arginine (11).

What is the principle of Sakaguchi test?

Principle of Sakaguchi test: The arginine reacts with α – napththol and an oxidizing agent such as bromine water or sodium hypochlorite/sodium hypobromite to give a red colored product. The other guanidinium containing compounds other than amino acid also give this reaction.

What does a positive Sakaguchi test indicate?

Positive result: A positive result on the Sakaguchi’s test is demonstrated by the formation of red color. This indicates the presence of an arginine or guanidinium compound. Negative result: A negative result in the Sakaguchi’s test is demonstrated by the absence of red color.

What amino acid gives positive result with Sakaguchi?

The Sakaguchi reagent is used to test for a certain amino acid and proteins. The amino acid that is detected in this test is arginine.

What is Sakaguchi reagent?

The Sakaguchi test is a chemical test used to detect presence of arginine in proteins. It is named after the Japanese food scientist and organic chemist, Shoyo Sakaguchi (1900–1995) who described the test in 1925. The Sakaguchi reagent used in the test consists of 1-Naphthol and a drop of sodium hypobromite.

What is the role of NaOH in lead acetate test?

Principle of Lead Sulfide Test Amino acids like cysteine and cystine release sulfur in the presence of strong alkaline conditions at a high temperature. The sulfur then combines with the alkali (NaOH) to form Na2 The Na2S thus formed reacts with lead acetate to form lead sulfide, which results in a black residue.

What is sodium nitroprusside test?

A test, using alkaline sodium nitroprusside and accitic acid as reagents, is described for detecting the presence of isoniazid and acetylisoniazid in urine. The test result is positive in all urine specimens collected at eight hours after administration of 200 mg. or 400 mg.

What is the chemical reaction in lead acetate test?

Lead acetate test paper is generally regarded as selective for detection of hydrogen sulfide (ASTM 2006). Hydrogen sulfide reacts with lead ions from the lead acetate to form solid lead sulfide PbS, a black solid. Hydrogen sulfide is released in the first few seconds after wool begins to burn (Spurgeon et al. 1977).

How does lead acetate precipitate proteins?

Lead acetate test: White precipitate is obtained White precipitate is obtained due to formation of lead albuminate therefore albumin is precipitated by heavy metal ions.

What is the principle of sodium nitroprusside reaction?

Principle of Nitroprusside Test The molecule, when combined with a sulfur atom forms a violet or red-colored complex. The action of a strong alkali releases SH group foud in cysteine molecule. The sulfur then reacts with the nitroprusside ion to form a red-colored compound.

What is the mechanism of action of nitroprusside?

Mechanism of action Sodium nitroprusside breaks down in circulation to release nitric oxide (NO). It does this by binding to oxyhaemoglobin to release cyanide, methaemoglobin and nitric oxide. NO activates guanylate cyclase in vascular smooth muscle and increases intracellular production of cGMP.

Why acetic acid is added in lead acetate test?

When acetic acid is used, complete precipitation of sulphur in the form of lead sulphate occurs due to common ion effect. Hence, it is necessary to use acetic acid for acidification of sodium extract for testing sulphur by lead acetate test.

What happens when lead acetate is added to protein?

Lead salts specially lead acetate tends to form insoluble salts and complexes with proteins. As any broth culture media contains high quantity of proteins, so it will form whit precipitate upon lead acetate addition.

What is the chemical composition of precipitate in the lead acetate test?

Lead acetate test: Take 3 ml of albumin solution in test tube then add 2 drops of 2% Na2NO3 solution and 1 ml of lead acetate solution. White precipitate is obtained White precipitate is obtained due to formation of lead albuminate therefore albumin is precipitated by heavy metal ions.

What is sodium nitroprusside test briefly explain its principle?

Nitroprusside test is a biochemical test used for the detection of the free –SH groups in amino acids or the cysteine amino acid in a protein. The test is a specific test for cysteine as it is the only amino acid with a free –SH group in the structure.

What is sodium nitroprusside test and its principle?

The nitroprusside test is used to detect the presence of ketoacids in the blood and the urine. This test measures only acetoacetate and acetone; therefore, it may underestimate the degree of ketonemia and ketonuria, because it will not detect the presence of beta-hydroxybutyrate (BOH).

What are the most common adverse reactions for nitroprusside?

Side Effects

• Chest pain or discomfort.
• fast, pounding, or irregular heartbeat or pulse.
• lightheadedness, dizziness, or fainting.
• slow heartbeat.
• trouble breathing.
• unusual tiredness.