Cabreira successfully appeals protease charge, 2nd time lucky

Well it sounds like a technicality, but it was enough to get him off...

Cabreira was suspended for two years in February for "tampering with a doping control sample". He was accused of using an enzyme called protease to defeat a doping control. The enzyme is able to break down traces of EPO in the urine. According to Lusa, Cabreira appealed the penalty on the grounds that the control had been conducted according to "methods not approved by the World Anti-Doping Agency" and that the offending substance "was not part of the list of banned products." It is the second time Cabreira has defeated a doping case on appeal. In August, 2008 he was suspended for ten months for failing a doping control, but the suspension was overturned on appeal.

If I understand this correctly, and I may not have a complete view, the appeal was won firstly because of irregularities in the way the sample was taken, leaving some doubt over who may or may not have altered the sample; and secondly because the enzyme in question is not a performance-enhancing substance taken by the athlete and thus listed as a banned product. Seems to me it should be listed, just as masking agents are (although in this case the agent is used outside of the body). Seems also logical that adding an enzyme - or anything, really - is tantamount to tampering with a sample. However in this case there was doubt, and the athlete quite rightly is given the benefit.

Portuguese roadie Cabreira suspended for alleged masking

It's hard to imagine anyone slipping a protease molecule into a dope-test sample and getting away with it, given how closely these things are "managed", but apparently it can happen. Well he'll be appealing, and here it is:Former LA-MSS rider and Portuguese road champion João Cabreira was suspended for two years for "tampering with a doping control sample", the Portuguese Cycling Federation announced Friday. The rider is the first to be suspended for a long-suspected technique of using an enzyme called protease to break down products such as EPO in the urine to cheat a doping control.

So what is "protease"? Well it's being a bit vague and mis-informative to say it's "an enzyme called protease", in fact it will be a specific hydrolase enzyme that targets a protein in the EPO molecule and breaks it down, just like molecules in your body break down, for example, food. Wikipedia says: A protease is any enzyme that conducts proteolysis, that is, begins protein catabolism by hydrolysis of the peptide bonds that link amino acids together in the polypeptide chain, which form a molecule of protein.

Why would an athlete use it? It was probably added to the urine sample post-micturition, hence the tampering allegation. A cyclist or other sportsperson may use it to break down (and thus mask) a banned substance such as EPO. By breaking down or digesting the target protein the banned substance becomes undetectable (at least in and of itself, as fragments or by-products of that protein may be detectable, and the absence of natural EPO would be suspicious).