Linked Life Data

9874207

Source:http://linkedlifedata.com/resource/pubmed/id/9874207

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-1-28
pubmed:databankReference
pubmed:abstractText
We have isolated cDNAs coding for the complete amino acid sequences of cholinesterase 1 (ChE1) and cholinesterase 2 (ChE2) from amphioxus. Both ChE transcripts have the characteristics of H-type catalytic subunits, which are inserted in the membrane via an ethanolamine-glycan-phosphatidylinositol anchor. The members of the catalytic triad of ChEs, the three pairs of cysteine residues involved in intrachain disulfide bonding, a cysteine near the carboxy terminal of both sequences, which could mediate interchain disulfide bonding, and 11 of the 14 aromatic amino acids that line the catalytic gorge of AChE are conserved. A remarkable difference between the two enzymes is in the region of the acyl-binding pocket, which plays an important role in determining substrate specificity in cholinesterases. ChE2 contains a sequence that resembles the acyl pocket of invertebrate ChE, while the acyl-binding site of ChE1 is novel. There are also differences between the two enzymes in the peripheral anionic site, which mediates inhibition by certain ligands. In vitro expression in COS-7 cells demonstrates that ChE2 hydrolyzes acetylthiocholine almost exclusively, while ChE1 hydrolyzes both acetylthiocholine and butyrylthiocholine. Both enzymes are inhibited comparably by BW284c51, but ChE1 is considerably more resistant to inhibition by propidium, ethopropazine, and eserine than is ChE2. Velocity sedimentation indicates that ChE1 and ChE2 are present as amphiphilic and nonamphiphilic G2 forms in vivo and in vitro. Another molecular form, which sediments at 17 S, is also present in vivo. Nondenaturing gel electrophoresis in conjunction with digestion by phosphatidylinositol-specific phospholipase C demonstrates that the vast majority of ChE1 and ChE2 is present as ethanolamine-glycan-phosphatidylinositol-anchored G2 forms in vivo. ChE1 also possesses an ethanolamine-glycan-phosphatidylinositol-anchor in vitro; however, ChE2 produced in vitro could not be detected on nondenaturing gels.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
419-29
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed-meshheading:9874207-Acetylthiocholine, pubmed-meshheading:9874207-Amino Acid Sequence, pubmed-meshheading:9874207-Animals, pubmed-meshheading:9874207-Binding Sites, pubmed-meshheading:9874207-Cholinesterases, pubmed-meshheading:9874207-Chordata, Nonvertebrate, pubmed-meshheading:9874207-Cloning, Molecular, pubmed-meshheading:9874207-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:9874207-Enzyme Inhibitors, pubmed-meshheading:9874207-Gene Expression, pubmed-meshheading:9874207-Hydrogen-Ion Concentration, pubmed-meshheading:9874207-Kinetics, pubmed-meshheading:9874207-Molecular Sequence Data, pubmed-meshheading:9874207-Recombinant Proteins, pubmed-meshheading:9874207-Sequence Analysis, DNA, pubmed-meshheading:9874207-Sequence Homology, Amino Acid, pubmed-meshheading:9874207-Ultracentrifugation
pubmed:year
1998
pubmed:articleTitle
cDNA cloning, in vitro expression, and biochemical characterization of cholinesterase 1 and cholinesterase 2 from amphioxus--comparison with cholinesterase 1 and cholinesterase 2 produced in vivo.
pubmed:affiliation
Division of Science and Mathematics, Birmingham-Southern College, Alabama 35254, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.