Tissue preparation protocols membrane

Translation-competent ER membrane fractions can also be prepared from tissue culture cells. We recommend a terminally differentiated secretory suspension cell line, such as a plasmacytoma (e.g., J558L), which contains abundant levels of ER membrane. In this protocol, cells are collected by centrifugation (5 min, 500 x g) and resuspended in a homogenization buffer containing 10 mMKOAc, 10 mMK-HEPES, pH 7.5, 1.5 mMMg(OAc)2,... 

In one study by Hood et al., 282 of 1153 identified proteins were identified by at least 2 unique tryptic peptides from FFPE prostate cancer (PCa) tissue.9 According to the gene ontology classification of the proteins identified, -65% of proteins were predicted to be intracellular proteins, while -50% of the total human proteome is predicted to be located in the intracellular compartment. Additionally, 20% of the proteins identified in the PCa tissue were classified as membrane proteins, which is significantly less than the predicted 40% for the human proteome. This relative disparity is not unexpected, considering the Liquid Tissue sample preparation kit lacks specific protocols for membrane protein extraction. The Liquid Tissue method has also been used for proteomics studies of a variety of FFPE tissue samples, including pancreatic tumors,28 squamous cell carcinoma,4 and oral human papillomavirus lesions.27... 

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