Role of temperature on protein and mRNA @entity12531 ( @entity12531 ) isozymes expression and XXXX oxidation by cultured @entity35 @entity409 .

@entity12284 @entity409 @entity4316 @entity7570 @entity2197 @entity70948 @entity12531 @entity35 @entity1363 @entity855
The @entity12531 ( @entity12531 )-mediated @entity1363 oxidation was studied in @entity35 @entity409 ( @entity409 ) maintained for 20hr at 4, 20 and 37 degrees, and further incubated for 8hr at 37 degrees. Either at 4 or 20 degrees, @entity1363 was oxidised by @entity409 at similar rates to that observed in freshly cut slices. Moreover, @entity409 kept a regioselectivity since 4-hydroxylation was more important than 1'-hydroxylation. Conversely, @entity409 totally lost their capacity to oxidise @entity1363 after 20hr at 37 degrees, and both @entity12284 protein and mRNA were not detected. @entity7570 protein was unaffected by a temperature of 37 degrees but its mRNA was totally lost. By blocking transcription with @entity4316 , the decay of both @entity12531 mRNAs followed the same profile at either 20 or 37 degrees, indicating that temperature affected the @entity12284 protein stability. Cell functionality was not involved in such an impairment since the low values of @entity855 , @entity2197 and protein synthesis rates observed at 4 and 20 degrees were rapidly restored, when @entity409 were further incubated at 37 degrees. The use of @entity35 supersomes expressing either @entity7570 or @entity12284 , strongly supported the hypothesis that @entity70948 was mainly formed by @entity12284 . These results suggest that: (1) @entity7570 protein is constitutive and largely expressed in @entity35 liver slices; (2) regioselective @entity1363 oxidation appears to be mainly @entity12284 dependent; and (3) since @entity12531 isoforms have similar half-lives (about 10-14hr), the loss of @entity12284 protein at 37 degrees might be due to a selective targeting (phosphorylation ?) leading to proteolytic disposal by the proteasome.
