General equation for protein degradation - (Feb/27/2006 )

Hello all!
Im trying to make a program to for automatic processing of peaklists for quantitative proteomics for this I need a general equation which describes the degradation of a unit protein over time, from the synthesis point. I have searched all day but not found anything usefull yet. Could you help me? The degradation rate will offcourse be different for different proteins but I expect all degradations to follow a general pattern which could be described with the eqation Im looking for.

Thank you ery much for any help

The two following papers may be of help:

[5] Ciechanover, A. and Schwartz, A.L. (1989) How are substrates recognized by the ubiquitin-mediated proteolytic system? Trends Biochem. Sci. 14, 483-488. [PubMed: 2696178]

[6] Varshavsky, A. (1997) The N-end rule pathway of protein degradation. Genes Cells 2, 13-28. [PubMed: 9112437]