title: Effects of a high-pressure treatment on the activity and structure of rabbit muscle proteasome.
abstract: The effects were assessed of high hydrostatic pressure on the activity and structure of rabbit skeletal muscle proteasome. The pressure effects on the activity were measured by the amount of fluorometric products released from synthetic substrates under pressure and from fluorescein isothiocyanate (FITC)-labeled casein after releasing the pressure. The effects on the structure were measured by fluorescene spectroscopy under pressure, and by circular dichroism (CD) spectroscopy and surface hydrophobicity after releasing the pressure. The optimal pressure for the hydrolyzing activity of synthetic peptides was 50 MPa. The degradation of FITC-labeled casein increased linearly with increasing pressure applied up to 200 MPa, and then markedly decreased up to at 400 MPa. The changes in the tertiary structure detected by fluorometric measurement were irreversible, whereas the changes in the secondary structure were small compared with those by heat treatment. The pressure-induced activation of proteasome therefore seems to have been due to a little unfolding of the active sites of proteasome.
authors.affiliation: Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata 950-2181, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Gerelt
authors.initials: G
authors.lastname: Borjigin
authors.forename: Kanna
authors.initials: K
authors.lastname: Masuda
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Ikeuchi
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Nishiumi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D002942:Circular Dichroism; D016650:Fluorescein-5-isothiocyanate / Q000737:chemistry; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D006874:Hydrostatic Pressure; D007700:Kinetics; D018482:Muscle, Skeletal / Q000201:enzymology*; D009842:Oligopeptides / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002364:Caseins; D009842:Oligopeptides; D046988:Proteasome Endopeptidase Complex; D016650:Fluorescein-5-isothiocyanate