Tuesday, October 20, 2009

Metalloproteomics

“Metalloproteomics” is a relatively new and not that widely known term. Today (20 October 2009), PubMed search produces only 13 hits. (The search for “metallomics” gives only twice as many hits.) The earliest use of the term is by Alfredo Sanz-Medel and by Scott et al. — incidentally, both papers were published online 23 December 2004.

Metalloproteomics by Eugene Permyakov (Wiley-Interscience, 2009) gives us a definition of the term:
Metalloproteomics is a proteomics of metal-binding proteins.
That’s easy, right? But wait. Check out the table of contents. It looks to me like another bioinorganic chemistry book, and a rather pricey one. It mostly deals with metalloproteins, but there are also Chapter 15, Interactions of metal cations with nucleic acids, and Chapter 16, “Nonphysiologic” metals. Nothing here is specifically proteomic or metallomic. I suppose that Chapter 3, Experimental methods used for studies of the binding of metal cations could be of some relevance to metalloproteomics. Then again, maybe not: how come that mass spectrometry, the most obvious proteomics technique, is not mentioned at all? And why metal cations only? Some metalloproteins contain vanadate. Maybe I am jumping to conclusions here (without even reading the book!), but this title is simply misleading.

Metalloproteomics (Wiley Series in Protein and Peptide Science)

Sunday, October 11, 2009

Metal instruments

This post was prompted by my recent exercises with trombone. Like many (but not all) brass instruments, trombone is actually made of brass, i.e. alloy of copper and zinc. Thus the English term “brass” is more pertinent than French cuivre or Russian медные (both mean “copper”). Still, it is misleading: saxophones (which are woodwind instruments) are also commonly made of brass. But then, I also heard of all-aluminium double bass which was patented in 1934 under the inconspicuous name “Musical instrument of the viol and violin type”.

Can one distinguish the sound of a silver flute from the sound of a gold flute? This study attempted to answer this question with a scientific experiment. Here’s the experimental setup:

A silver coated, full silver, 9 carat gold, 14 carat gold, 24 carat gold, platinum coated and all-platinum flute was played by 7 professional flutists (members of Viennese orchestras including the Vienna Philharmonic orchestra) in an anechoic chamber.

And the result?

As expected, the most significant assigned expressions for all instruments were the “contradictionary <contradictory?> expressions”: for example, the sound color of each instrument was evaluated as “bright” and simultaneously as “dark” or “full/round” and “thin/sharp”.
Tests with experienced professional flutists and listeners and one model of a flute made by Muramatsu from 7 different materials showed no evidence that the wall material has any appreciable effect on the sound color or dynamic range of the instrument. The common stereotypes used by flutists and flute makers are exposed as “stereotypes”.
So there. It’s a shame that Muramatsu does not make aluminium flutes.