Palmitoyl(protein) hydrolase

  (Redirected from Palmitoyl protein thioesterase)

Palmitoyl protein hydrolase/thioesterases are enzymes (EC 3.1.2.22) that remove thioester-linked fatty acyl groups such as palmitate from modified cysteine residues in proteins or peptides during lysosomal degradation. It is an enzyme that catalyzes the chemical reaction

Palmitoyl protein thioesterase
1eh5 opm.png
Palmitoyl protein thioesterase 1. Red plane shows hydrocarbon boundary of the lipid bilayer
Identifiers
SymbolPalm_thioest
PfamPF02089
Pfam clanCL0028
InterProIPR002472
SCOP21exw / SCOPe / SUPFAM
OPM superfamily127
OPM protein1eh5
palmitoyl [protein] hydrolase
Identifiers
EC no.3.1.2.22
CAS no.150605-49-5
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
palmitoyl[protein] + H2O palmitate + protein

Thus, the two substrates of this enzyme are [[palmitoyl[protein]]] and H2O, whereas its two products are palmitate and protein.

This enzyme belongs to the family of hydrolases, specifically those acting on thioester bonds. The systematic name of this enzyme class is palmitoyl[protein] hydrolase. Other names in common use include palmitoyl-protein thioesterase, and palmitoyl-(protein) hydrolase. This enzyme participates in fatty acid elongation in mitochondria.

Neuronal ceroid lipofuscinoses (NCL) represent a group of encephalopathies that occur in 1 in 12,500 children. Mutations in the palmitoyl protein thioesterase gene causing infantile neuronal ceroid lipofuscinosis.[1] The most common mutation results in intracellular accumulation of the polypeptide and undetectable enzyme activity in the brain. Direct sequencing of cDNAs derived from brain RNA of INCL patients has shown a mis-sense transversion of A to T at nucleotide position 364, which results in substitution of Trp for Arg at position 122 in the protein - Arg 122 is immediately adjacent to a lipase consensus sequence that contains the putative active site Ser of PPT. The occurrence of this and two other independent mutations in the PPT gene strongly suggests that defects in this gene cause INCL.

ExamplesEdit

Human proteins containing this domain include:

palmitoyl-protein thioesterase 1
Identifiers
SymbolPPT1
Alt. symbolsPPT
NCBI gene5538
HGNC9325
OMIM600722
RefSeqNM_000310
UniProtP50897
Other data
EC number3.1.2.22
LocusChr. 1 p32
palmitoyl-protein thioesterase 2
Identifiers
SymbolPPT2
Alt. symbolsG14
NCBI gene9374
HGNC9326
OMIM603298
RefSeqNM_138717
UniProtQ9UMR5
Other data
EC number3.1.2.22
LocusChr. 6 p21.3

Structural studiesEdit

As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes 1EH5, 1EI9, 1EXW, and 1PJA.

See alsoEdit

ReferencesEdit

  1. ^ Hofmann SL, Vesa J, Hellsten E, Verkruyse LA, Camp LA, Rapola J, Santavuori P, Peltonen L (1995). "Mutations in the palmitoyl protein thioesterase gene causing infantile neuronal ceroid lipofuscinosis". Nature. 376 (6541): 584–587. Bibcode:1995Natur.376..584V. doi:10.1038/376584a0. PMID 7637805. S2CID 4322423.

Further readingEdit

External linksEdit

This article incorporates text from the public domain Pfam and InterPro: IPR002472