The isolation and purification of anaerobic bacteria present in the rumen is a difficult task. The isolation of rumen organisms from rumen contents diluted as much as 100 billion times was accomplished by a technique described by Gall et al. (1947). Hungate (1947) published a method for isolating anaerobic cellulose digesters from the rumen, and Sijpesteijn (1948) also described anaerobic techniques for isolating cellulose-decomposing bacteria from the rumen of cattle. None of these techniques is completely satisfactory for the isolation of many important rumen organisms.

The presence of the dense hydroxyapatite matrix within human bone limits the applicability of conventional protocols for protein extraction. This has hindered the complete and accurate characterization of the human bone proteome thus far, leaving many bone-related disorders poorly understood. We sought to refine an existing method of protein extraction from mouse bone to extract whole proteins of varying molecular weights from human cranial bone. Whole protein was extracted from human cranial suture by mechanically processing samples using a method that limits protein degradation by minimizing heat introduction to proteins. The presence of whole protein was confirmed by western blotting. Mass spectrometry was used to sequence peptides and identify isolated proteins. The data have been deposited to the ProteomeXchange with identifier PXD003215. Extracted proteins were characterized as both intra- and extracellular and had molecular weights ranging from 9.4-629 kDa. High correlation scores among suture protein spectral counts support the reproducibility of the method. Ontology analytics revealed proteins of myriad functions including mediators of metabolic processes and cell organelles. These results demonstrate a reproducible method for isolation of whole protein from human cranial bone, representing a large range of molecular weights, origins and functions.

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