What molecular machine is responsible for forming an enzyme?

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megamind-616 eNotes educator| Certified Educator

Enzymes are proteins that help to speed up chemical reactions with the body (in other words, enzymes are biological catalysts). Like all proteins, enzymes are created during protein synthesis. The biomolecules that are a part of protein synthesis are: DNA, nucleotides, RNA (m, t and r), and amino acids (the building blocks of proteins).

Protein synthesis begins with DNA transcription in the nucleus. During DNA transcription, DNA unwinds. One strand of the DNA serves as the template to create a single-stranded mRNA (messenger RNA). Codons are sets of three nucleotides on an mRNA. These codons will be important later on in the process of protein synthesis. The mRNA then travels through a nuclear pore of the nucleus into the cytoplasm. 

Once in the cytoplasm, ribosomes attach to the mRNA. The ribosomes help to read the codons of the mRNA and match them to anticodon on the bottom of a tRNA. Anticodons are simply sets of three nucleotides that contain the complementary nucleotide base pairs to mRNA codons. On the top of a tRNA is an attached amino acids. 

The ribosome, the molecular machine which manufactures proteins within all cells, is an RNA enzyme.  (Alex Taylor, "Artificial enzymes created"; University of Cambridge)

The ribosome travels down the mRNA (this is called translation). As it does so, additional tRNA anticodons  are matched with their complementary codons. Once two amino acids are next to one another, a peptide bond is formed. As this process continues, a polypeptide chain is formed. Protein synthesis stops once the ribosome hits a stop codon (a codon that does not code for an amino acid). At this point, the polypeptide chain (a primary protein structure) is released.

Polypeptide chains then undergo additional processing to make either secondary, tertiary or quaternary protein structures.  The shape of a protein (enzymes) determines its function. The lock and key analogy is often used to describe how proteins function. Enzymes are shaped uniquely for particular substrates, which is explained via this hyperlink.

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