What are the three types of proteins? Proteins can be divided into 3 categories according to their f

In nutrition, food proteins are divided into three categories according to the types and quantities of amino acids contained in food proteins: 1. Complete protein: This is a class of high-quality protein. They contain a complete range of essential amino acids, in sufficient quantities, and in appropriate proportions with each other.

This type of protein not only supports human health, but also promotes growth and development. The proteins in milk, eggs, fish, and meat are all complete proteins. 2. Although semi-complete proteins contain a complete range of amino acids, the number of some amino acids cannot meet the needs of the human body.

They can sustain life, but they do not promote growth and development. For example, gliadin in wheat is a semi-complete protein with very little lysine. One or several amino acids contained in food that are different from what the body needs are called limiting amino acids.

Cereal proteins tend to contain less lysine, so their limiting amino acid is lysine. 3. Incomplete proteins This type of protein cannot provide all the essential amino acids needed by the human body, and they alone can neither promote growth and development, nor can they sustain life. For example, the collagen in the skin of meat is an incomplete protein.

Proteins are divided into according to their nutritional value; Complete protein'There are 3 categories of semi-complete proteins and incomplete proteins.

Acidic amino acids, neutral amino acids, basic amino acids?

There should be more than three categories of proteins by function, for example:

1. Structural functions (structural proteins) such as fibrin, keratin, collagen and residual protein.

Wait; 2. Catalytic function (protease) In addition to a small amount of nucleic acids in the organism.

In addition to the enzymes that catalyze biochemical reactions, most of the enzymes are proteins, such as amylase.

3. Transport function ** transport protein) The transport of specific substances in the organism is completed by rotten proteins, such as hemoglobin to transport oxygen.

4. Immune function (antibodies, etc.) Antibodies, complement, and interferons secreted by immune cells.

Wait; 5. Recognition function (glycocoat) The so-called glycocoat is a complex of proteins and sugars on the cell surface, which plays the function of intercellular recognition.

6. Other functional proteins are decoded.

Proteins are divided into two categories according to their shape, not three.

According to the classification of molecular shape, the ratio of the long and short axes of the protein molecular shape is less than 10 is called globular protein, and the ratio of the long and short axes of the protein molecular shape is greater than 10 is called fibrous protein. There is no third category.

There are other ways to classify proteins.

According to the composition classification, the molecular composition containing only amino acids is called simple protein, and the molecular composition contains a non-protein part in addition to the protein part is called the bound protein, of which the non-protein part is called the prosthetic group.

There are many types of proteins and complex structures, and to date there is no ideal way to classify them. For example, from the shape of the protein, they can be divided into globular protein and fibrous protein; In terms of composition, it can be divided into simple egg late Qianchang white matter (the molecule only contains amino acid residues) and bound protein (in addition to amino acids, there are non-amino acid substances in the molecule, the latter is called a progroup); Simple proteins can be divided into albumin (also known as albumin), globulin, glutelin, prolamine, protamine, histone, scleroprotein, etc. according to their physical and chemical properties. Binding proteins can be divided into nucleoprotein, phosphoprotein, metalloprotein, chromoprotein, etc. according to their different cosylgroups.