Identification of methionine-containing proteins and quantitation of their methionine contents
The authors developed an in vitro labeling method that allows identification of methionine-containing proteins after separation on gel electrophoresis and quantitation of their methionine contents. Proteins were separated by polyacrylamide gel electrophoresis under denaturing conditions, blotted onto nitrocellulose membrane, and reacts with (1-/sup 14/C)iodoacetic acid at pH 2. Autoradiography revealed bands of varying intensities depending on their methionine contents. Proteins of known amino acid compositions and soybean storage proteins were used to establish the specificity and the optimum conditions for the reaction. The ratio of the densitometry scan of the autoradiogram to that of nitrocellulose membrane stained for protein gave an accurate index of the methionine content in each protein band. This method has considerable potential in the identification of methionine-rich polypeptides in legumes and other plant crops where methionine is the most limiting essential amino acid. It should also be generally useful for proteins where methionine is of interest.
- Research Organization:
- Univ. of California, Berkeley (USA)
- OSTI ID:
- 6956722
- Journal Information:
- J. Agric. Food Chem.; (United States), Vol. 35:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PROTEINS
CHEMICAL COMPOSITION
ACETIC ACID
AUTORADIOGRAPHY
CARBON 14 COMPOUNDS
ELECTROPHORESIS
IN VITRO
METHIONINE
AMINO ACIDS
CARBOXYLIC ACIDS
DRUGS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
550201* - Biochemistry- Tracer Techniques