Van - Slyke estimation of amino acids).
The Van Slyke estimation of amino acids is a method used to determine the amino acid composition of a protein or other biological sample. It was named after its inventor, Donald D. Van Slyke, who developed the technique in the early 20th century.
The estimation involves a series of chemical reactions and measurements to determine the concentration of each individual amino acid in the sample. The basic steps of the Van Slyke estimation are as follows:
1. Hydrolysis: The protein or sample is hydrolyzed, or broken down, into individual amino acids. This is usually done by heating the sample in acid, such as hydrochloric acid. The hydrolysis breaks the peptide bonds between the amino acids, resulting in free amino acids.
2. Derivatization: The free amino acids are then derivatized, or chemically modified, to make them easier to measure. This is typically done by reacting the amino acids with a reagent, such as ninhydrin or dansyl chloride, which forms a colored compound with the amino acids.
3. Measurement: The derivatized amino acids are then measured using a spectrophotometer or other analytical instrument. The absorbance of the colored compound is proportional to the concentration of the amino acid, allowing for quantification.
4. Calibration: To accurately determine the concentration of each amino acid, a calibration curve is prepared using known concentrations of standard amino acids. The absorbance of the standards is measured, and a calibration curve is plotted relating absorbance to concentration.
5. Calculation: The absorbance of the derivatized amino acids from the sample is then compared to the calibration curve to determine the concentration of each amino acid. This can be done using mathematical calculations or by interpolation on the calibration curve.
The Van Slyke estimation of amino acids is widely used in biochemistry and protein research to determine the composition of proteins and other biological samples. It allows for the quantification of individual amino acids, which is important for understanding protein structure, function, and metabolism.