There are a diverse amount of proteins. There is no specific phrase to encompass the broad subject of proteins, except with a broad phrase: If there is a job to be done in the body, proteins do it. Here is a list of different types of proteins and their functions:
Enzymes: Speed up chemical reactions
Keratin: Make up skin, hair, and nails
Insulin: Regulates sugar between cells, blood, and the liver
Antibodies: Defend body against foreign invaders
Hemoglobin: Carriers oxygen in the blood
Collagen: Responsible for the flexibility in skin, corneas, and blood vessels
Lipoproteins: Carry fat and cholesterol in blood
Receptors: In the cell membrane, they inform the cell of chemicals and other proteins
Neurotransmitters/Hormones: Set off the receptors
Channels/Pores: Filters flow through the cell membranes
Roles differ between proteins because of the different shapes they may resemble and chemical formulas they may have.
The primary structure of proteins is based on the long chains of amino acids. These amino acids are peptide bonded together. Amino acids come in different types, thus the different order in which the amino acids are placed because the addition of different variables, such as heme, phosphate, or sugars, or the modification of their order can determine the different structures and functions protein molecules may posses.
Also, when there are two cysteines present in a protein, they are usually covalently bonded together to form a disulphide bridge in the protein, which is a part of the primary structure of the protein.
C = Cysteines
Cysteine amino acids are actually adjacent to each other, but do not have to be right next to each other in a polypeptide link, when creating a disulphide bridge. The above picture gives an idea of how it is made.
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were fully composed, as well as altered images and diagrams, by Josh Eisma (2002), unless otherwise specified.
