RGD Reference Report - Identification of microsomal rat liver carboxylesterases and their activity with retinyl palmitate. - Rat Genome Database

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Identification of microsomal rat liver carboxylesterases and their activity with retinyl palmitate.

Authors: Sanghani, SP  Davis, WI  Dumaual, NG  Mahrenholz, A  Bosron, WF 
Citation: Sanghani SP, etal., Eur J Biochem 2002 Sep;269(18):4387-98.
RGD ID: 724430
Pubmed: PMID:12230550   (View Abstract at PubMed)

Retinyl esters are a major endogenous storage source of vitamin A in vertebrates and their hydrolysis to retinol is a key step in the regulation of the supply of retinoids to all tissues. Some members of nonspecific carboxylesterase family (EC 3.1.1.1) have been shown to hydrolyze retinyl esters. However, the number of different isoenzymes that are expressed in the liver and their retinyl palmitate hydrolase activity is not known. Six different carboxylesterases were identified and purified from rat liver microsomal extracts. Each isoenzyme was identified by mass spectrometry of its tryptic peptides. In addition to previously characterized rat liver carboxylesterases ES10, ES4, ES3, the protein products for two cloned genes, AB010635 and D50580 (GenBank accession numbers), were also identified. The sixth isoenzyme was a novel carboxylesterase and its complete cDNA was cloned and sequenced (AY034877). Three isoenzymes, ES10, ES4 and ES3, account for more than 95% of rat liver microsomal carboxylesterase activity. They obey Michaelis-Menten kinetics for hydrolysis of retinyl palmitate with Km values of about 1 micro m and specific activities between 3 and 8 nmol.min-1.mg-1 protein. D50580 and AY034877 also hydrolyzed retinyl palmitate. Gene-specific oligonucleotide probing of multiple-tissue Northern blot indicates differential expression in various tissues. Multiple genes are highly expressed in liver and small intestine, important tissues for retinoid metabolism. The level of expression of any one of the six different carboxylesterase isoenzymes will regulate the metabolism of retinyl palmitate in specific rat cells and tissues.



Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
Ces1dRatretinoid metabolic process involved_inTAS PMID:12230550UniProt 
Ces1dl1Ratretinoid metabolic process involved_inTAS PMID:12230550UniProt 
Ces1eRatretinoid metabolic process involved_inTAS PMID:12230550UniProt 
Ces1fRatretinoid metabolic process involved_inTAS PMID:12230550UniProt 
Ces2cRatretinoid metabolic process involved_inTAS PMID:12230550UniProt 
Ces2eRatretinoid metabolic process involved_inTAS PMID:12230550UniProt 

Cellular Component

  

Molecular Function

  

Objects Annotated

Genes (Rattus norvegicus)
Ces1d  (carboxylesterase 1D)
Ces1dl1  (carboxylesterase 1D like 1)
Ces1e  (carboxylesterase 1E)
Ces1f  (carboxylesterase 1F)
Ces2a  (carboxylesterase 2A)
Ces2c  (carboxylesterase 2C)
Ces2e  (carboxylesterase 2E)

Objects referenced in this article
Gene Esd esterase D Rattus norvegicus

Additional Information