Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.5 (neuropathy target esterase)
 1,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Retinol esterified with long-chain fatty acids is a common dietary source of vitamin A, that is hydrolyzed prior to absorption. An intrinsic brush border membrane retinyl ester hydrolase activity had previously been demonstrated for rat small intestine [Rigtrup, K. M., & Ong, D. E. (1992) Biochemistry 31, 2920-2926]. This activity has now been purified to apparent homogeneity by a three-column procedure to obtain a protein of apparent molecular weight of 130,000. The purified protein retained the pattern of bile salt stimulation, specificity for the acyl moiety of the retinyl ester, and the Km values previously observed for the activity present in the isolated brush border membrane. This protein also had a potent phospholipase activity, while having little measurable ability to hydrolyze triacylglyceride and cholesteryl ester substrates. The retinyl ester hydrolase enzyme was localized to the distal two-thirds of the small intestine. A polyclonal antiserum against rat brush border phospholipase B reacted with the purified retinyl ester hydrolase, strongly suggesting that this enzyme was the same as that previously purified and characterized as a calcium-independent brush border phospholipase B [Pind, S., & Kuksis, A. (1991) Biochem. Cell Biol. 69, 346-357]. Detailed kinetic studies revealed lower Km values for retinyl palmitate substrate compared to phosphatidylcholine substrate, with all tested bile salts. The Km values for each substrate were bile salt dependent and differently altered when bile salts were changed. Vmax values were also bile salt dependent. Retinyl palmitate was hydrolyzed most rapidly in the presence of deoxycholate and least rapidly in taurocholate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification and partial characterization of a retinyl ester hydrolase from the brush border of rat small intestine mucosa: probable identity with brush border phospholipase B. 811 29

Homologues to Carboxylesterase NP and Candida rugosa lipase, used for the chiral separation of racemic mixtures of 2-arylpropionic methyl esters, were identified by BLAST searches of available genome sequences for hyperthermophilic microorganisms. Two potential candidates were identified: a putative lysophospholipase from Pyrococcus furiosus (Pfu-LPL) and a carboxylesterase from Sulfolobus solfataricus P1 (Sso-EST1). Although both enzymes showed hydrolytic preference toward the (S) methyl ester, only Sso-EST1 yielded highly optically pure (S) naproxen (%ee(p) >/= 90) and was thus further investigated. Changes in pH or reaction time showed little improvement in %ee(p) or E values with Sso-EST1. However, the addition of 25% methanol resulted in a 25% increase in E. The effect of various cosolvents on the enantiomeric ratio showed no correlation with the log P or dielectric constant values of the solvent. However, an inverse relationship between E and the denaturation capacity (DC) of the water miscible cosolvents was observed. This was attributed to an increase in enzyme flexibility with increasing solvent DC values leading to a concomitant reduction in the resolving power of Sso-EST1. The results here show that although bioinformatics tools can be used to select candidate biocatalysts for chiral resolution of 2-arylpropionic esters, biochemical characterization is needed to definitively determine functional characteristics.
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PMID:Strategic selection of hyperthermophilic esterases for resolution of 2-arylpropionic esters. 1452