kinase assay with histone h1 - (Sep/20/2006 )
For kinase assays there are a range of potential substrates that could be used: MBP, casein, histone h1.
Does anyone know why one would be used over another? The reason I'm asking is that we have lots of histone h1 and I figured I might as well use it.
rather old-fashioned way to assay protein kinases; in earlier days where kinases were classically purified, and no specific substrates were available, casein or histones were used for radio-active phosphorylation assays, because 1) each can multiple phosphorylated by various kinases, 
they are cheap; if you know your kinase try to design an assay with a known substrate to get optimum responses, and to compare it with literature data
That was an absurd response. In no way is it old-fashioned to do assays this way. I could pick a substrate specific to my kinase, but why spend $400 on 10ug of recombinant protein when MBP sells for $30 at 1mg.
My questions wasn't why use MBP, casein or histone at all, my question was why use one of these over the other? How does histone h1 compare to MBP as a general substrate, for example? Have people had experiences where one worked as a substrate and the other didn't?
i think that depends on the enzyme you're actually studying...
I was under the impression that casein and MBP were virtually interchangeable for most kinases, and that histone was generally used for tyrosine kinases, but I'm not sure if this is true.