Osborne classification, proteins

It is possible to classify proteins on several different bases. One basis is on the cereal from which they come and where in the seed they are found, another is the Osborne classification system, which is based on the solubility of the protein. Proteins can be further classified in chemical terms such as molecular weight and the presence or absence of sulfur. 

The Osborne classification, which dates from 1907, was updated at a symposium on gluten in 1996. Gianibelli el al. point out that at least 1300 peptides can be obtained from wheat endosperm proteins after disulfide bond rupture using two-dimensional fractionation.6... 

Where MW is the molecular weight (kD) and Wr is the rate of sub-unit weight (%) in raw materials. 50% amidation rates of aspartic and glutamic acids are supposed for peanut proteins, keratin, collagen, and gelatin. Amino acid ratios (mol/100 mol) -A-non-ionized polar (Asn, Cys, Gin, His, Ser, Thr, Tyr), -B- ionized polar (Arg, Asp, Glu, Lys) and -C- non-polar (Ala, He, Leu, Met, Phe, Pro, Trp, Val). S is the solubility of proteins according to Osborne classification I- in water, II- in diluted salt solutions, III-in diluted acidic or basic solutions, and IV- in ethanol (80%) solutions Miscellaneous associations. 

Work on the solubility was continued by Osborne to produce the classifications of vegetable proteins that are still used. Studies of the solubility of proteins remains important both in characterising and purifying proteins. 

QS, like those of other plants, store proteins in the embryo to provide nutrients for growth and development (Herman and Larkins, 1999). In the food area, proteins stored in seeds are the source of the proteins consumed directly as food by humans (Shewry et al., 1995). Stored proteins provide building blocks for rapid growth upon seed and pollen germination (Herman and Larkins, 1999). Osborne (1924) introduced a classification of plant proteins based on their solubility in a series of solvents, such as albumins in water, and globulins in saline. 

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