Protein

Protein

1. Proteins are large biomolecules or macromolecules that are comprised of one or more long chains of amino acid residues.

2. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides.

3. proteins only exist for a certain period and are then degraded and recycled by the cell's machinery through the process of protein turnover. A protein's lifespan is measured in terms of its half-life and covers a wide range.

4. Proteins may be purified from other cellular components using a variety of techniques such as ultracentrifugation, precipitation, electrophoresis, and chromatography

5. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues.

6. The sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the genetic code specifies 20 standard amino acids

7. Most proteins fold into unique 3D structures. The shape into which a protein naturally folds is known as its native conformation. Although many proteins can fold unassisted, simply through the chemical properties of their amino acids, others require the aid of molecular chaperones to fold into their native states. Biochemists often refer to four distinct aspects of a protein's structure: Primary structure: the amino acid sequence. A protein is a polyamide. Secondary structure: regularly repeating local structures stabilized by hydrogen bonds. The most common examples are the-helix, β-sheet and turns. Because secondary structures are local, many regions of different secondary structure can be present in the same protein molecule. Tertiary structure: the overall shape of a single protein molecule; the spatial relationship of the secondary structures to one another. Tertiary structure is generally stabilized by nonlocal interactions, most commonly the formation

8. Many proteins are composed of several protein domains, i.e. segments of a protein that fold into distinct structural units.

9. roteins are the chief actors within the cell, said to be carrying out the duties specified by the information encoded in genes.[26] With the exception of certain types of RNA, most other biological molecules are relatively inert elements upon which proteins act.