Molec Cell protein modifications

covalent modifications list (8)

1. ubiquitination

2. phosphorylation

3. glycosylation

4. lipid modification

5. methylation

6. acetylation

7. SUMOylation

8. Mono-ubiquitination

non-covalent modifications list (4)

ions, ATP/ADP, GTP/GDP, proteolysis

ubiquitination function and culprit/enzyme

• function: targeting proteins for degradation

• culprit/enzyme: E1, 2, 3 Ubiquitin conjugating enzymes

phosphorylation function and culprit/enzyme

• function: activates/inactivates proteins

• culprit/enzyme: kinases, phosphatases

glycosylation function and culprit/enzyme

• function: adds sugars to extracellular matrix proteins; modifications can alter protein structure

• culprit/enzyme: glycosyltransferases, glycosidases

lipid modification function and culprit/enzyme

• function: specific enzymes covalently attach to target proteins, changes how proteins behave, helping them attach to cell membranes

• culprit/enzyme: lipid transferases

methylation function and culprit/enzyme

• function: reversible, post-translational mod where methyl group (CH₃) is added to specific AA side chains or proteins termini

• culprit/enzyme: methyltransferase

acetylation function and culprit/enzyme

• function: adds acetyl group to (CH₃CO) to a molecule

• culprit/enzyme: lysine or histone acetyltransferases (KATS) or (HATS)

SUMOlyation function and culprit/enzyme

• function: reversible, small ubiquitin-like modifier (SUMO) protein attaches to target protein to change its function, location, stability

• culprit/enzyme: E1, E2, E3 ubiquitin enzymes

mono-ubiquitination function and culprit/enzyme

• function: single ubiquitin molecule attaches to lysine residue on target protein

• culprit/enzyme: E1, E2, E3 ubiquitin enzymes, deubiquitinating enzymes (DUBs)

ions function and culprit/enzyme

• function: interaction through direct electrostatic attraction between fully charged groups

• culprit/enzyme: inherent to protein

ATP/ADP function and culprit/enzyme

• function: alters protein conformation to turn it on or off

• culprit/enzyme: ATP synthase, ATPases

GTP/GDP function and culprit/enzyme

• function: alters protein conformation to turn it on or off (same as ATP)

• culprit/enzyme: guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs)

proteolysis function and culprit/enzyme

• function: breakdown of proteins into smaller peptides of AAs through hydrolysis of peptide bonds

• culprit/enzyme: proteases