Proteinase K: An Enzyme for Everyone

protein expression purification and analysisWe recently posted a blog about Proteinase K, a serine protease that exhibits broad cleavage activity produced by the fungus Tritirachium album Limber. It cleaves peptide bonds adjacent to the carboxylic group of aliphatic and aromatic amino acids and is useful for general digestion of protein in biological samples. In that previous blog we focused on its use to remove RNase and DNase activities. However, the stability of Proteinase K in urea and SDS and its ability to digest native proteins make it useful for a variety of applications. Here we provide a brief list of peer-reviewed citations that demonstrate the use of proteinase K in DNA and RNA purification, protein digestion in FFPE tissue samples, chromatin precipitation assays, and proteinase K protection assays: Continue reading “Proteinase K: An Enzyme for Everyone”

STATs and ChIPs- Learning A Lesson Or Two About Transcriptional Activation

During my childhood, my family and I spent many a vacation in the Swiss Alps.  From the mountain tops I used to look out into the horizon as far as the eye could see with peak upon peak stretching out into the distance.  If I was lucky, I would have a map that allowed me to identify each peak, perhaps even distinguish the highest from the lowest and thus really get a sense that I understood the underlying topography.  However, I quickly realized how little I actually knew about the vast, undulating Swiss countryside.  What I had initially observed as a homogenous ‘mat’ of peaks stretching out into the horizon was in fact a rippling of deep valleys that would make an afternoon hike anything but a walk in the breeze. 

Looking back on these experiences I am struck by how closely they reflect the landscape of modern science— a broad mat of detailed knowledge with its own peaks of specialization.  I am reminded of the words of writer Bill Bryson who described science as “tens of thousands of people that do tiny, tiny things that all accrete into a larger body of knowledge” (1).  Continue reading “STATs and ChIPs- Learning A Lesson Or Two About Transcriptional Activation”