Bovine muscle 20S proteasome. III: Quantification in tissue crude extracts using ELISA and radial immunodiffusion techniques and practical applications.

The 20S proteasome is a large complex (700kDa) that exhibits endo- and exo-peptidase activities with wide specificity. In postmortem muscles, several sets of evidence suggest a possible significant contribution of proteasome to meat tenderisation. Hence, an accurate and rapid quantification procedure is needed to attest that new function during the ageing of meat.

Bovine muscle 20S proteasome. II: Contribution of the 20S proteasome to meat tenderization as revealed by an ultrastructural approach.

The role of the 20S proteasome proteolytic effects was revisited using an ultrastructural approach with the aim to explain some particular structural changes identified in type I muscles and in high pH meat. In both types of meat, major changes observed after ageing are an increase in the thickness of the Z-line followed by the appearance of an amorphous protein structure spreading out over the I-band. This was followed by a total degradation of this amorphous structure and of the Z-line.

Bovine muscle 20S proteasome: I. Simple purification procedure and enzymatic characterization in relation with postmortem conditions.

Over the last decade, several sets of evidence support a possible contribution of the 20S proteasome to the meat tenderizing process. This assumption was emphasized by recent investigations demonstrating that the 20S proteasome was active in the absence of activators and exhibited endo- and exoproteolytic activities, a status often strongly debated before. In the present work, we developed a new rapid and simple purification procedure for muscle 20S proteasome and revisited the physicochemical properties of this complex in relation with the postmortem muscle environmental conditions, i.

Development and evaluation of a sandwich ELISA for quantification of the 20S proteasome in human plasma.

Because quantification of the 20S proteasome by functional activity measurements is difficult and inaccurate, we have developed an indirect sandwich enzyme-linked immunosorbent assays (ELISA) for quantification of the 20S proteasome in human plasma. This sandwich ELISA uses a combination of a monoclonal antibody (mcp 20) recognizing the C2-beta subunit of human 20S proteasome (Mr approximately 30,000) and a polyclonal rabbit anti-20S antibody which labels different subunits of the complex. The detection limit of the assay was established as 10 ng/ml (n=10, mean of zero standard+2 S.

Plasma proteasome level is a potential marker in patients with solid tumors and hemopoietic malignancies.

Background: Proteasomes are nonlysosomal proteolytic structures that have been implicated in cell growth and differentiation. Abnormal expression levels of proteasomes have been described in tumor cells, and proteasomes can be detected and measured in plasma. The objective of this study was to characterize differences in proteasome levels between normal, healthy donors and patients with neoplastic disease and to correlate the findings with clinical status and other biologic markers of disease spread.