So far there are six SUMO proteases in humans that have been designated SENP1-3 and SENP5-7 (sentrin/SUMO-specific protease).1 The six proteases possess a conserved C-terminal domain which are variable in size, and with a distinct N-terminal domain between them. The C-terminal domain shows catalytic activity and N-terminal domain regulates cell localization and substrate specificity.[8]
SENP1 (Sentrin-specific protease 1) is a human protease of 643 amino acids with a weight of 73 kDa, EC number in humans 3.4.22.B70, which adopts a conformation that identifies it as a member of the superfamily of cysteine proteases contain a catalytic triad with characterized three amino acids: a cysteine at position 603, a histidine at position 533 and aspartic acid at position 550. The important nucleophile is cysteine located at the N-terminal alpha helix of the protein core, the other two amino acids, aspartate and histidine, are located in a beta sheet end. [9]
Both SENP1 are located in the nucleus and cytosol depending on the cell type, although it has been seen that is exported out from the nucleus to the cytosol through a sequence of nuclear export (NES) that is located at the C-terminus. The mammalian SENP1 is localized mainly in the nucleus.[10]
SENP1 catalyzes maturation SUMO protein (small ubiquitin-related modifier), which causes hydrolysis peptide bond of SUMO is in a conserved sequence Gly-Gly-|-Ala-Thr-Tyr at the C-terminal [11] to be added to the conjugation of other proteins (sumoylation).[12] In vertebrates there are three members of the family of SUMO: SUMO-1, -2 and -3. SENP1 can catalyze any of these three. This conjugation of SUMO toward other proteins is a lot like ubiquitination, however these modifications leads to different results depending on the type of protein been modified.[13]
