If you interested in finding blogs in your subject area, then the following blog search engines will prove useful in helping you to locate some:
http://www.technorati.com/
http://www.icerocket.com/
http://blogsearch.google.com/
http://uk.ask.com/?o=312&l=dir
Image taken from http://www.irs-review.org.uk/sillysearchtemplate.htm
......and a blog or two to whet your appetite!
http://wordpress.com/tag/biochemistry/
http://scienceblogs.com/
Happy Hunting:-)