Protein: It can be defined as consisting of a carbon amino acid that is attached to an amino group (-NH2), an acid group (-COOH), hydrogen and a radical group variable.
Rating: If the protein is composed only of amino acids, called holoproteína when in addition to amino acids exhibits any other type of molecule called heteroproteína.
Amino acids are organic compounds that are characterized by a carboxyl group and an amino group. Solid, crystalline, high melting point, soluble in water with optical activity and chemical behavior amphoteric, depending on the pH can ionize as an acid, base or both at once.
Peptide bond: The peptides are formed by joining amino acids through a enlce peptídico.Es a covalent bond that develops between the carboxyl group of an amino acid and the amino group of the next, leading to detachment of a water molecule.
Protein structure: Primary structure-is the amino acid sequence of the protein, indicates that amino acids make up the polypeptide chain and the order in which amino acids are found. Secondary structure - is the willingness of the amino acid sequence and space. As they remain bound during the synthesis of proteins and turning ability because of their links, are acquiring a stable spatial arrangement. There are 3 types of secondary structure:a-h Elice and collagen helix conformation. Tertiary structure-Covers the provision of secondary structure of a polypeptide to fold upon itself causing a globular conformation that facilitates its solubility in water and in salt solutions. Proteins that fail to form secondary tertiary structures remain elongated, resulting in filamentous proteins. Quaternary Structure-Reports of the joint by weak bonds of several polypeptide chains to form a protein complex.

Properties of proteins: Solubility-globular proteins give rise to colloidal dispersions by their large size. Establishing hydrogen bonds with water molecules that coat protein is one to avoid ue other proteins. Denaturation "If there are changes in pH, temperature, changes in protein concentrations ... are not functional, they lose their ability to perform the function for which they were designed. They can sometimes recover its original shape, is called renaturation. Specificity-In its amino acid sequence proteins have variable stable sectors and sectors in which the amino acids can be replaced by others without altering the function of molécula.Esto allows each species has their specific proteins and even create differences between individuals of the same species.-Buffering capacity tend to neutralize the pH of the medium changes because they can behave as a base or an acid and thereby release or remove protons.
Globular proteins: Collagen-appear in connective tissues, cartilagenosos, integumentary and bone. A-keratin-appear in nails, hair, feathers, wool ... Elastin-appear in tendons and blood vessel walls. A-keratin-appear in the threads of silk.
Functions of proteins: Structure-forming part of the cytoskeletal microtubules of cilia and flagella and associated histones to DNA.Trans-substances in the body such as hemoglobin that transports oxygen in the blood. Enzyme-promotes chemical reactions that occur in body cells. Hormone-biocatalysts are active throughout the body, such as growth hormone. Defense Antibodies whose function is to neutralize foreign substances that enter the body. contractile-structures that allow contraction and relaxation of muscle fibers. Reserve. Homeostatic - adjust the pH.