Linked Life Data

3805054

Source:http://linkedlifedata.com/resource/pubmed/id/3805054

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1987-3-23
pubmed:abstractText
Dopamine beta-hydroxylase is present in the bovine adrenal medulla in two forms: soluble and membrane-bound. In a previous study, it was shown that the tetrameric, soluble form of the enzyme undergoes dissociation into two identical dimeric subunits and that this subunit dissociation is dependent on pH and ADP binding (Dhawan, S., Hensley, P., Osborne, J. C., Jr., and Fleming, P. J. (1986) J. Biol. Chem. 261, 7680-7684). Here we report the effect of pH and ADP on the dissociation of the membranous form of dopamine beta-hydroxylase into two nonidentical subunits. Negative stain electron microscopy of purified membranous hydroxylase showed largely tetrameric species together with occasional dimeric species. The tetrameric images of membranous hydroxylase were similar to, but clearly different from, previously published negative stain images of soluble hydroxylase (Duong, L. T., Fleming, P. J., and Ornberg, R. L. (1985) J. Biol. Chem. 260, 2393-2398). Quantitative binding of ADP to the membranous hydroxylase revealed the existence of two binding sites per dimeric subunit. ADP binding and low pH both promote dissociation of a hydrophilic, catalytically active subunit from the membranous enzyme reconstituted onto phospholipid vesicles. Kinetic analyses of reconstituted membranous hydroxylase activity were consistent with the existence of tetrameric and dimeric catalytic species in equilibrium. All of the hydrophilic subunits of the purified soluble hydroxylase bind to the hydrophobic subunits of the reconstituted membranous hydroxylase. We propose that, in the chromaffin granules, the soluble hydroxylase subunits are in equilibrium association with the membrane-bound hydroxylase subunits and that the hydrophilic subunits of both soluble and membranous hydroxylase are identical.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1869-75
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Subunit exchange between membranous and soluble forms of bovine dopamine beta-hydroxylase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.