Protein storage function

Other plasma vitamin B 2 proteins, transcobalamines I and III, appear to have primarily a storage function and only a lesser role in transport. 

The seeds of dicotyledonous plants have two cotyledons, or seed leaves, which are part of the embryo. The cotyledons usually are the main storage tissue, although in some plants (such as castor bean) the endosperm also has a storage function. During development in the field, seeds gradually accumulate storage oils, proteins and carbohydrates (Table 3.1). In the seed, the cotyledon structure is relatively simple. The remainder of the embryo, the embryonic axis, consists mostly of undifferentiated cells, but provascular tissue can be detected that develops into vascular tissue in the seedling. 

They are also the major structural constituent of living systems. According to the central dogma of molecular biology [3], information is transferred from DNA to RNA to proteins. DNA functions as a storage medium for the information necessary to synthesize proteins, and RNA is responsible for (among other things) the translation of this information into protein molecules. 

Storage function Some proteins provide a way to store small molecules or ions. Ovalbumin, for example, is a stored form of amino acids that is used by embryos developing in bird eggs. Casein, a milk protein, and gliadin, in wheat seeds, are also stored forms of protein intended to nourish animals and plants, respectively. Ferritin, found in all cells of the body, attaches to iron ions and forms a storage complex in humans and other animals. 

Proteins that enable the cell to perform special functions within the organism, e.g., hemoglobin, muscle proteins, storage proteins, cilial proteins and exoproteins, such as collagen blood plasma proteins, antibodies, milk proteins, and proteohormones, structural and regulatory proteins required for the specialized function of the cell, etc. 

---