Skip to main content

Protein Translation

Protein Translation

Protein translation is the process of synthesizing proteins from amino acids. This series of reactions translates the code provided to messenger ribonucleic acid or RNA (mRNA) by deoxyribonucleic acid or DNA into a sequence of amino acids that makes up the active protein molecule. Protein synthesis begins with a strand of mRNA synthesized in response to the genetic code located in a gene on a strand of DNA. The process of translation is slightly different in eukaryotic cells from that in prokaryotic cells; for the sake of simplicity, translation in prokaryotes will be discussed here.

Proteins are made up of combinations of the twenty common amino acids. Placement of each amino acid is specified by a three-nucleotide codon. Four different nucleotides are available to code; taken three at a time, they can form sixty-four combinations. Some amino acids have more than one codon (a phenomenon known as redundancy). Translation also requires a start codon and stop codon.

Four general actions comprise protein translation: The mRNA binds to a ribosome ; amino acids are carried to the ribosome by transfer RNA (tRNA); the amino acids are joined, forming peptide bonds; and the completed protein molecule is released from the ribosome. The synthetic processes are called initiation, elongation, and termination and are assisted by protein factors essential for each step.

Adenosine triphosphate (ATP) provides energy for the attachment of amino acids by specific enzymes to tRNA. For reference, the ends of DNA and RNA strands are designated 5 and 3. Translation begins with attachment of the 5-end of mRNA to the small unit of a ribosome. A tRNA molecule carrying formylmethionine attaches to the ribosome at a location matching the initiation codon (AUG) on mRNA. The large subunit of the ribosome then attaches to this complex, forming a complete, active ribosome. During periods of rapid translation, a number of ribosomes may cluster together with mRNA, forming polyribosomes. A second tRNA brings another amino acid to the ribosome, matching the codon on mRNA for the second amino acid. A peptide bond forms between the two amino acids, and the first tRNA is released.

Guanosine triphosphate (GTP) provides energy to move the growing peptide chain along as mRNA passes through the ribosome. As more amino acids are added, the polypeptide chain grows longer until the ribosome reaches the stop codon of mRNA.

When the growing peptide chain approaches the carboxylic acid end (at the stop codon on mRNA), protein termination factors help to disassemble the ribosome and release the completed protein chain. Protein translation is interrupted by antibiotics such as tetracycline or chloramphenicol that interfere with protein synthesis.

see also Codon; Proteins; Protein Synthesis; Ribonucleic Acid.

Dan M. Sullivan


Devlin, Thomas M., ed. (2002). Textbook of Biochemistry: With Clinical Correlations, 5th edition. New York: Wiley-Liss.

McKee, Trudy, and McKee, James R. (2003). Biochemistry: The Molecular Basis of Life, 3rd edition. Boston: McGraw-Hill.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Protein Translation." Chemistry: Foundations and Applications. . 18 Apr. 2019 <>.

"Protein Translation." Chemistry: Foundations and Applications. . (April 18, 2019).

"Protein Translation." Chemistry: Foundations and Applications. . Retrieved April 18, 2019 from

Learn more about citation styles

Citation styles gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).

Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.

Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, cannot guarantee each citation it generates. Therefore, it’s best to use citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:

Modern Language Association

The Chicago Manual of Style

American Psychological Association

  • Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
  • In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.