Linked Life Data

6299819

Source:http://linkedlifedata.com/resource/pubmed/id/6299819

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1983-5-27
pubmed:abstractText
Cyclic AMP phosphodiesterase (PDE) activity reaches a peak during the aggregation stage of development where it functions to regulate extracellular levels of cAMP. During the subsequent differentiation of the two cell types at the culmination stage, the activity reappears but only in stalk cells. We found that extracts from the culmination stage contained PDE which could be activated by preincubation with Mg2+ and dithiothreitol (DTT), a treatment which is known to release an endogenous inhibitor from the aggregation stage enzyme. When the culmination stage extracts were subjected to chromatography on Biogel P300, two peaks of activity were eluted, PDE-I (Mr greater than 260,000) and PDE-II (Mr 100,000). Treatment of the fractions with Mg-DTT did not affect the low-molecular-weight enzyme but caused activation of the high-molecular-weight enzyme and the appearance of a third, intermediate form. Kinetic analysis of the two peaks revealed Km values for cAMP of 2 mM and 10 microM for PDE-I and PDE-II, respectively. We tested the possibility that these forms of the enzyme might be distributed differently in the two cell types by measuring the Km for cAMP and the effect of Mg-DTT treatment on isolated sections of stalk and spore cells. The spore sections contained a high Km form of the enzyme (0.3 mM) which was activated by preincubation with Mg . DTT whereas stalk sections contained a low Km form (3 microM) which was not affected by the activation treatment. We conclude that both cell types contain enzyme protein and that the apparent localization of PDE activity in stalk cells is due to the inhibition of activity in spore cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0012-1606
pubmed:author
pubmed:issnType
Print
pubmed:volume
96
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
296-303
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Cell type specific inhibition of cAMP phosphodiesterase activity during terminal differential in Dictyostelium discoideum.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.