Holoprotein

A holoprotein is a protein that is made up exclusively of a sequence of amino acids. It is synonymous with simple protein. Currently, holoprotein is understood as the union of the amino acid sequence with its prosthetic group; forming a conjugated protein (the amino acid sequence that does not have a prosthetic group is the apoprotein).

Classification

Holoproteins are classified into:

Albumins

These proteins are water soluble, found in all cells of the body and also in the bloodstream. Some examples of albumins are lacto albumins found in milk and serum albumins found in blood.

Globulins

These proteins are soluble in water and in dilute salt solutions with strong acids and their bases. Examples of globulins are milk lactoglobulin and ovoglobulin.

Gluteins

These proteins are soluble in dilute acids and alkalis. Wheat glutelin protein is a good example of glutelins. These only occur in plant material.

Prolamines

These proteins are soluble in 70 to 80% alcohol. Among them we can highlight wheat fliadin and corn zein. They are found only in plant materials.

Albumonoids

Albuminoids or selenoproteins are insoluble in all neutral solvents, dilute alkalis, and acids. They are found in connective tissues, hair and nails. Some examples are keratin, found in the keratinized layers of the skin and in the cortex or cortex of hair and nails, and collagen found in the white fibers of areolar tissue.

Histones

These are water-soluble proteins in which amino basic acids are predominant. They are rich in arginine or lysine. Chromosome DNA eukaryotes associate with histones in the formation of nucleoproteins.

Protamines

These proteins are soluble in water and in basic polypeptides of low molecular weight (approximately 4,000 daltons). They are very rich in arginine amino acids. The polypeptide chain consists of 28 amino acid residues, including 19 arginines and 8 or 9 non-basic amino acids. Protamines are bound to the DNA of the sperm of some fish. Some examples of protamines are salmin (from salmon) and sturgein (from sturgeons).