The findings published in the Journal of Proteome Research is the latest dataset in an ongoing controversy over which biochemical remnants can be detected in the dino.
In the study, Marshall Bern, Brett S. Phinney and David Goldberg point out that the first analysis in 2007 (see Did Dinosaurs Become Chickens?) of a well-preserved, fossilized T. rex bone identified traces of seven distinct protein fragments, or peptides, from collagen. That material is one of the primary components of bone, tendons and other connective tissue
However, later studies disputed that finding, suggesting that it was a statistical fluke or the result of contamination from another laboratory sample (see Soft Dinosaur Tissue Dispute - Probably Just Biofilm, Says Study).
The latest study describes reanalysis of the T. rex data and says they also found evidence of substances found in collagen. "In summary, we find nothing obviously wrong with the Tyrannosaurus rex [analysis from 2007]," the report states. "The identified peptides seem consistent with a sample containing old, quite possibly very ancient, bird-like bone, contaminated with only fairly explicable proteins. Hemoglobin and collagen are plausible proteins to find in fossil bone, because they are two of the most abundant proteins in bone and bone marrow."
Article: Marshall Bern, Brett S. Phinney, David Goldberg, 'Reanalysis of Tyrannosaurus rex Mass Spectra', J. Proteome Res., Article ASAP Publication Date (Web): July 15, 2009 doi:10.1021.pr900349r