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Research has been conducted on ubiquitin-specific processing protease family of deubiquitinating enzymes. The crystal structure of the catalytic core domain of ubiquitin-specific processing protease family representative HAUSP has been stidied both in isolation and in complex with ubiquitin aldehyde, and the details are reported.

Peptide aldehydes which inhibit primary peptidase activities of the 26S and 20S proteasomes are utilized to determine the importance of proteasome in antigen presentation. Peptide aldehydes retard the degradation of ubiquitinated protein and protein substrates by 26S particles and inhibit the abnormal, short-lived polypeptides and long-lived proteins in intact cells. Aldehydes block the presentation on major histocompatibility complex (MHC) class I molecules in ovalbumin, when ovalbumin is injected into lymphoblast cytosols. Proteolytic generation in MHC class I molecules is prevented by aldehyde inhibitors.

Research has been conducted on Oct-1 coactivator OCA-S which is important for histone H2B transcription. The authors have investigated the functional identification and purification of OCA-S activity, and they report that the characterization of this cofactor has identified the role for the p38 subunit which is identical to glyceraldehyde-3-phosphate dehydrogenase, and that p38 mediates S phase-inducible H2B promoter activation.

The author discusses the study on histone gene expression in mammalian cells. The topics of interest include the role of enzyme glyceraldehyde-3-phosphate dehydrogenase in the OCA-S coactivator complex, and redox dependence on in vitro transcription of histone genes.