Quaternary structure - what is this (Nov/10/2010 )

Dear all,

what does the Quaternary structure mean?

I have read the definition, but I have to show the Quaternary structure of an enzym (Gamma-glutamyl hydrolase), but I am not sure what they mean by this?

any ideas?

tertiary structure is the three dimensional structure of a protein subunit (or the whole protein if only one subunit)

quaternary structure is the subunit structure of the protein (three dimensional arrangement of the subunits).

Quaternary structure belongs to the heirarchy of protein structure which includes and begins with primary, secondary (alpha helix, beta-sheet), tertiary and quaternary structure.
Quaternary structure is the assembly of different tertiary units or domains to be correct in one complex structure. best example is Hb (hemoglobin) and LDH (lactate dehydrogenase).hope it explains u :-)