STORAGE PROTEIN

Definition of storage protein

• Biological reserves of metal ions and amino acids used by organisms.

• Serve as reserves of metal ions and amino acids which can be mobilized and utilized for the maintenance and growth of organisms.

FUNCTION OF STORAGE PROTEIN

• To store metal ions such as iron and amino acids in our body.

EXAMPLE OF STORAGE PROTEIN

• Ferritin : stores iron in body• Some storage protein stores amino acids such

as animals and plants. Animals : Casein(milk-based protein) and

ovalbumin( egg whites)Plants : Seeds particularly leguminous plant

FERRITIN• Ubiquitos intracellular protein that stores iron

and releases it in a controlled fashion.• The amount of ferritin stored reflects the

amount of iron stored.• The protein is produced by almost all living

organisms, including algae, bacteria, higher plants and animals.

• In humans, it acts as a buffer againts iron deficiency and iron overload.

STRUCTURE OF FERRITIN

Function of ferritin• Serves to store iron in a non-toxic form, to

deposit it in a safe form and transport it to areas where it is required.

• Act as immune response• Stress response

Storage protein in animal

• Casein• Ovalbumin

Casein

CASEIN STRUCTURE

• They are “complete proteins” or “storage protein” because they contain all amino acids essential for building blood and tissue and can sustain life and provide normal growth even if they are the only proteins in diet.

• Milk contains 3 kinds of protein : caseins, lactoalbumins and lactoglobulins, all of which are globular protein.

Ovalbumin

OVALBUMIN STRUCTURE

• Ovalbumin is a glycoprotein that comprises 54% of the total protein of the egg white.

• The function of albumin is unknown, although it is presumed to be a storage protein.

• Ovalbumin is an important protein in several different areas of research, including :-general studies of protein structure and properties.

• Structure :The ovalbumin protein of chickens is made up of 385 amino acids.

Storage protein in plant

• Seeds particularly of leguminous plants, contains higher concentrations of storage protein. Up to 25% of the dry weight of the seed can be composed of storage protein.

• Storage protein in plant serve as nitrogen sources for the developing embryo during germination.

• Besides seeds, storage proteins can also be found in root and shoot tubers, like in potatoes.

TUBER

SEED