The regulation of enzymes by small molecules that bind to a site distinct from the active site, changing the conformation and catalytic activity of the enzyme.
aminoacyl tRNA synthetase
An enzyme that joins a specific amino acid to a tRNA molecule carrying the correct anticodon sequence.
anticodon
The nucleotide sequence of transfer RNA that forms complementary base pairs with a codon sequence on messenger RNA.
autophagy
The degradation of cytoplasmic proteins and organelles by their enclosure in cytoplasmic vesicles that fuse with lysosomes.
chaperone
A protein that facilitates the correct folding or assembly of other proteins.
dolichol phosphate
A lipid molecule in the endoplasmic reticulum upon which oligosaccharides are assembled for the glycosylation of proteins.
elongation factor
A protein involved in the elongation phase of transcription or translation.
glycolipid
A lipid consisting of two hydrocarbon chains linked to a polar head group containing carbohydrates.
glycoprotein
A protein linked to oligosaccharides.
glycosylation
The addition of carbohydrates to proteins.
glycosylphosphatidylinositol (GPI) anchor
A glycolipid containing phosphatidylinositol that anchors proteins to the external face of the plasma membrane.
initiation factor
A protein that functions in the initiation stage of translation.
lysosome
A cytoplasmic organelle containing enzymes that break down biological polymers.
microRNA (miRNA)
A naturally-occurring short noncoding RNA that acts to regulate gene expression.
monocistronic
Messenger RNAs that encode a single polypeptide chain.
nitrosylation
Protein modification by addition of NO groups to the side chains of cysteine residues.
N-myristoylation
The addition of myristic acid (a 14-carbon fatty acid) to the N-terminal glycine residue of a polypeptide chain.
palmitoylation
The addition of palmitic acid (a 16-carbon fatty acid) to cysteine residues of a polypeptide chain.
peptidyl prolyl isomerase
An enzyme that facilitates protein folding by catalyzing the cis-trans isomerization of prolyl peptide bonds.
polycistronic
Messenger RNAs that encode multiple polypeptide chains.
polysome
A series of ribosomes translating a messenger RNA.
prenylation
The addition of specific types of lipids (prenyl groups) to C terminal cysteine residues of a polypeptide chain.
proteasome
A large protease complex that degrades proteins tagged by ubiquitin.
protein disulfide isomerase
An enzyme that catalyzes the formation and breakage of disulfide (S–S) linkages.
protein kinase
An enzyme that phosphorylates proteins by transferring a phosphate group from ATP.
protein phosphatase
An enzyme that reverses the action of protein kinases by removing phosphate groups from phosphorylated amino acid residues.
protein-serine/threonine kinase
A protein kinase that phosphorylates serine and threonine residues.
protein-tyrosine kinase
A protein kinase that phosphorylates tyrosine residues.
proteolysis
Degradation of polypeptide chains.
release factor
A protein that recognizes stop codons and terminates translation of mRNA.
ribosome
A particle composed of RNA and proteins that is the site of protein synthesis.
RNA interference (RNAi)
The degradation of mRNAs by short complementary double-stranded RNA molecules.
ribosomal RNA (rRNA)
The RNA component of ribosomes.
Shine-Dalgarno sequence
The sequence prior to the initiation site that correctly aligns bacterial mRNAs on ribosomes.
signal peptidase
An enzyme that removes the signal sequence of a polypeptide chain by proteolysis.
signal sequence
A hydrophobic sequence at the amino terminus of a polypeptide chain that targets it for secretion in bacteria or incorporation into the endoplasmic reticulum in eukaryotic cells.
small interfering RNA (siRNA)
A short noncoding double-stranded RNA that acts in the RNA interference pathway.
transfer RNA (tRNA)
An RNA molecule that functions as an adaptor between amino acids and mRNA during protein synthesis.
ubiquitin
A highly conserved protein that acts as a marker to target other cellular proteins for rapid degradation.
