Re: Can proteinase K inactivate lysozymes?

That is an excellent question that shows a good understanding of lysozyme and proteinase K. While proteinase K would act to inactivate lysozyme, that is not the primary purpose for including it when preparing genomic DNA. As is explained in Current Protocols in Molecular Biology, proteinase K is included primarily to degrade proteins that would otherwise end up as impurities in the genomic DNA. The bacterial cell (actually all cells) contain a large number of proteins that have a high affinity for DNA because they play a role in gene transcription and/or chromatin structure. The presence of these proteins in your genomic DNA sample can make it difficult to perform additional experiments using the DNA.

There are a number of good listings of molecular biology protocols on the WWW, some of which also include good discussions of the theory behind the protocol. Here are a few examples:

http://reserach.nwfsc.noaa.gov/protocols.html

http://www.horizonpress.com/gateway/protocols.html

http://www.protocol-online.net

Hope this information is useful to you.