What Are the Steps of Protein Synthesis?

Protein synthesis refers to the process by which organisms synthesize proteins based on genetic information on messenger ribonucleic acid (mRNA) transcribed from DNA. Protein biosynthesis is also called translation, which is the process of changing the sequence of bases in mRNA molecules into the sequence of amino acids in proteins or polypeptide chains.

Protein synthesis

Prokaryotes and

Ribosomal size subunit, mRNA

Peptide chain extension

Regulation of protein synthesis

The rate of protein synthesis in the body is mainly at the level of transcription, and secondly it is regulated and controlled during translation. It is affected by a variety of factors such as gender, hormones, cell cycle, growth and development, health status and living environment, as well as changes in numerous biochemical substances involved in protein synthesis. Because translation and transcription of prokaryotes are usually coupled together and their mRNAs have a short life span, the speed of protein synthesis is mainly determined by the speed of transcription. Weakening is a way to regulate the speed of translation by first affecting the transcription through the excess and deficiency of translation products. The structure and properties of mRNA can also regulate the rate of protein synthesis.

HCR Two states of protein synthesis HCR

Eukaryotic transcription and translation are not coupled, and protein synthesis is usually slower than prokaryotes. In addition to the regulation of eukaryotes mainly through transcription and post-transcriptional processing and the structure and properties of mRNA (such as cap structure and poly A tail) (see messenger ribonucleic acid), studies on globin biosynthesis have shown The start factor eIF-2 is the limiting factor for translation speed, so the factors affecting eIF-2 can regulate the translation speed. In vitro studies using mammalian reticulocyte-free preparations indicate that when hemoglobin is lacking, there is no need to synthesize proteins because hemoglobin cannot be formed. Experiments have shown that the regulation of heme is achieved through a type called heme-regulated repressor (HCR). HCR has active and inactive forms

Effect of protein synthesis on heme

Heme regulates proteins by affecting eIF-2. When heme is present, it inhibits cellular protein synthesis and also promotes the synthesis of proteins by cells that normally do not synthesize hemoglobin, such as the protein synthesis of cell-free preparations of liver cancer cells, Hella cells, and ascites tumor cells.

Protein synthesis protein inhibitor

Inhibitors of protein biosynthesis Many inhibitors of protein biosynthesis are highly specific, which is important for studying the mechanism of synthesis. Many clinically effective antibiotics work by specifically inhibiting protein synthesis in prokaryotes. They inhibit bacterial growth without damaging human cells. Using the differences in the synthesis of two types of biological proteins, drugs can be found to treat diseases caused by bacterial infections. The table lists some of the more important inhibitors of protein biosynthesis, their sites of action, and specificity.