The yeast Tsa1 peroxiredoxin is a ribosome-associated antioxidant

2008 ◽  
Vol 412 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Eleanor W. Trotter ◽  
Jonathan D. Rand ◽  
Jill Vickerstaff ◽  
Chris M. Grant
Keyword(s):  
Molecular Mass ◽  
Ribosomal Proteins ◽  
Growth Control ◽  
Thioredoxin Reductase ◽  
Cysteine Residue ◽  
Error Rates ◽  
High Molecular Mass ◽  
Disease States ◽  
Thioredoxin System ◽  
Lower Molecular Mass

The yeast Tsa1 peroxiredoxin, like other 2-Cys peroxiredoxins, has dual activities as a peroxidase and as a molecular chaperone. Its peroxidase function predominates in lower-molecular-mass forms, whereas a super-chaperone form predominates in high-molecular-mass complexes. Loss of TSA1 results in aggregation of ribosomal proteins, indicating that Tsa1 functions to maintain the integrity of the translation apparatus. In the present study we report that Tsa1 functions as an antioxidant on actively translating ribosomes. Its peroxidase activity is required for ribosomal function, since mutation of the peroxidatic cysteine residue, which inactivates peroxidase but not chaperone activity, results in sensitivity to translation inhibitors. The peroxidatic cysteine residue is also required for a shift from ribosomes to its high-molecular-mass form in response to peroxide stress. Thus Tsa1 appears to function predominantly as an antioxidant in protecting both the cytosol and actively translating ribosomes against endogenous ROS (reactive oxygen species), but shifts towards its chaperone function in response to oxidative stress conditions. Analysis of the distribution of Tsa1 in thioredoxin system mutants revealed that the ribosome-associated form of Tsa1 is increased in mutants lacking thioredoxin reductase (trr1) and thioredoxins (trx1 trx2) in parallel with the general increase in total Tsa1 levels which is observed in these mutants. In the present study we show that deregulation of Tsa1 in the trr1 mutant specifically promotes translation defects including hypersensitivity to translation inhibitors, increased translational error-rates and ribosomal protein aggregation. These results have important implications for the role of peroxiredoxins in stress and growth control, since peroxiredoxins are likely to be deregulated in a similar manner during many different disease states.

scholarly journals Effect of diosgenin on biliary cholesterol transport in the rat

1993 ◽  
Vol 291 (3) ◽  
pp. 793-798 ◽  
Author(s):  
A Thewles ◽  
R A Parslow ◽  
R Coleman
Keyword(s):  
Bile Salt ◽  
Molecular Mass ◽  
Bile Salts ◽  
Mass Fraction ◽  
Gel Permeation Chromatography ◽  
High Molecular Mass ◽  
Cholesterol Transport ◽  
Biliary Cholesterol ◽  
Lower Molecular Mass ◽  
Salt Depletion

Biliary cholesterol output in rats was stimulated over 3-fold by feeding diosgenin for 5 days, whereas biliary outputs of phospholipid and bile salts were not changed by diosgenin feeding. Isolating and perfusing the liver without bile salts resulted in a rapid and substantial decrease in biliary bile salt output; bile salt depletion abolished the diosgenin-induced increment in biliary cholesterol output, showing that the diosgenin-elevated biliary cholesterol output was bile-salt-dependent. Diosgenin treatment also produced a significant decrease in biliary alkaline phosphodiesterase I. Fresh bile obtained from control and diosgenin-fed rats was subjected to gel-permeation chromatography in order to separate different-sized biliary cholesterol carriers. Two major peaks of cholesterol were eluted, with cholesterol also being eluted between the peaks. The cholesterol peak eluted at the lower molecular mass (20-30 kDa) was observed in all bile samples. The higher-molecular-mass peak, which was eluted at the void volume, was not observed in all biles; control biles contained very little high-molecular-mass form of cholesterol, whereas biles from the diosgenin group contained up to 47% of cholesterol in the high-molecular-mass fraction. Diosgenin treatment produced a range of elevated biliary cholesterol values which positively correlated with the proportion of cholesterol contained in the high-molecular-mass fraction (r = 0.98). The results show that diosgenin induced a marked bile-salt-dependent increase in biliary cholesterol output and a shift in biliary cholesterol transport to higher-molecular-mass structures.

scholarly journals The purification of tissue inhibitor of metalloproteinases-2 from its 72 kDa progelatinase complex. Demonstration of the biochemical similarities of tissue inhibitor of metalloproteinases-2 and tissue inhibitor of metalloproteinases-1

1991 ◽  
Vol 278 (1) ◽  
pp. 179-187 ◽  
Author(s):  
R V Ward ◽  
R M Hembry ◽  
J J Reynolds ◽  
G Murphy
Keyword(s):  
Molecular Mass ◽  
Polyclonal Antiserum ◽  
High Molecular Mass ◽  
U937 Cells ◽  
Tissue Inhibitor Of Metalloproteinases ◽  
Gingival Fibroblasts ◽  
Tissue Inhibitor ◽  
Lower Molecular Mass ◽  
Inhibitory Activities

Human gingival fibroblasts in culture were shown to secrete a 72 kDa progelatinase, of which a proportion in the medium was found to be complexed with tissue inhibitor of metalloproteinases-2 (TIMP-2). A purification procedure was devised to purify free enzyme and inhibitor. We also describe the purification of both 95 kDa progelatinase bound to TIMP-1 and free 95 kDa progelatinase from the medium of U937 cells. A polyclonal antiserum to TIMP-2 was prepared and it was shown that TIMP-1 and TIMP-2 are antigenically distinct. The ability to form stable complexes and the relative inhibitory activities of TIMP-1 and TIMP-2 towards 95 kDa and 72 kDa gelatinases, collagenase, stromelysins 1 and 2 and punctuated metalloproteinase were determined; only minor differences were found. Complex-formation between TIMP-2 and 72 kDa progelatinase was demonstrated not to reduce the metalloproteinase-inhibitory activity of TIMP-2, a finding that led to the characterization of high-molecular-mass TIMP activity. Competition experiments between progelatinases and active gelatinases for TIMPs indicated that the affinity of TIMPs for progelatinases is weaker than that for active gelatinases. In a study of the effects of TIMP-1 and TIMP-2 on progelatinase self-cleavage we found that both TIMP-1 and TIMP-2 inhibit the conversion of 95 kDa and 72 kDa progelatinases and prostromelysin into lower-molecular-mass forms. TIMP capable of complexing with progelatinase was shown to be no more efficient an inhibitor of gelatinase self-cleavage than TIMP not able to complex with progelatinase.

scholarly journals Degradation of Humic Acids by the Litter-Decomposing Basidiomycete Collybia dryophila

2002 ◽  
Vol 68 (7) ◽  
pp. 3442-3448 ◽  
Author(s):  
Kari Timo Steffen ◽  
Annele Hatakka ◽  
Martin Hofrichter
Keyword(s):  
Humic Acid ◽  
Molecular Mass ◽  
Manganese Peroxidase ◽  
Forest Litter ◽  
High Molecular Mass ◽  
Water Soluble ◽  
Strong Indication ◽  
Lower Molecular Mass ◽  
Single Protein ◽  
Key Enzyme

ABSTRACT The basidiomycete Collybia dryophila K209, which colonizes forest soil, was found to decompose a natural humic acid isolated from pine-forest litter (LHA) and a synthetic 14C-labeled humic acid (14C-HA) prepared from [U-14C]catechol in liquid culture. Degradation resulted in the formation of polar, lower-molecular-mass fulvic acid (FA) and carbon dioxide. HA decomposition was considerably enhanced in the presence of Mn2+ (200 μM), leading to 75% conversion of LHA and 50% mineralization of 14C-HA (compared to 60% and 20%, respectively, in the absence of Mn2+). There was a strong indication that manganese peroxidase (MnP), the production of which was noticeably increased in Mn2+-supplemented cultures, was responsible for this effect. The enzyme was produced as a single protein with a pI of 4.7 and a molecular mass of 44 kDa. During solid-state cultivation, C. dryophila released substantial amounts of water-soluble FA (predominantly of 0.9 kDa molecular mass) from insoluble litter material. The results indicate that basidiomycetes such as C. dryophila which colonize forest litter and soil are involved in humus turnover by their recycling of high-molecular-mass humic substances. Extracellular MnP seems to be a key enzyme in the conversion process.

scholarly journals Antioxidant Activity of the Yeast Mitochondrial One-Cys Peroxiredoxin Is Dependent on Thioredoxin Reductase and Glutathione In Vivo

2009 ◽  
Vol 29 (11) ◽  
pp. 3229-3240 ◽  
Author(s):  
Darren Greetham ◽  
Chris M. Grant
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Thioredoxin Reductase ◽  
Disulfide Bridge ◽  
Cysteine Residue ◽  
In Vitro Assays ◽  
Redox Partner ◽  
Thioredoxin System

ABSTRACT Peroxiredoxins are ubiquitous enzymes which protect cells against oxidative stress. The first step of catalysis is common to all peroxiredoxins and results in oxidation of a conserved peroxidatic cysteine residue to sulfenic acid. This forms an intermolecular disulfide bridge in the case of 2-Cys peroxiredoxins, which is a substrate for the thioredoxin system. 1-Cys Prx's contain a peroxidatic cysteine but do not contain a second conserved cysteine residue, and hence the identity of the in vivo reduction system has been unclear. Here, we show that the yeast mitochondrial 1-Cys Prx1 is reactivated by glutathionylation of the catalytic cysteine residue and subsequent reduction by thioredoxin reductase (Trr2) coupled with glutathione (GSH). This novel mechanism does not require the usual thioredoxin (Trx3) redox partner of Trr2 for antioxidant activity, although in vitro assays show that the Trr2/Trx3 and Trr2/GSH systems exhibit similar capacities for supporting Prx1 catalysis. Our data also indicate that mitochondria are a main target of cadmium-induced oxidative stress and that Prx1 is particularly required to protect against mitochondrial oxidation. This study demonstrates a physiological reaction mechanism for 1-Cys peroxiredoxins and reveals a new role in protection against mitochondrial heavy metal toxicity.

High-molecular-mass alkaline phosphatase in serum and bile: physical properties and relationship with other high-molecular-mass enzymes.

1981 ◽  
Vol 27 (6) ◽  
pp. 860-866 ◽  
Author(s):  
P M Crofton ◽  
A F Smith
Keyword(s):  
Alkaline Phosphatase ◽  
Liver Disease ◽  
Molecular Mass ◽  
Negative Charge ◽  
High Molecular Mass ◽  
Enzyme Complex ◽  
Alkaline Ph ◽  
Large Size ◽  
Lower Molecular Mass ◽  
Net Charges

Abstract High-molecular-mass alkaline phosphatase has similar properties in serum and bile. It is of sufficiently large size to be excluded by Sepharose 6B and carries a high negative charge at alkaline pH, largely accounted for by the presence of sialic acid residues. It is slightly more heat labile than the lower-molecular-mass liver isoenzyme. Other enzymes originating from the hepatocyte plasma membrane are present as similar high-molecular-mass forms in normal bile, and in both bile and serum from patients with liver disease. The activities of these relatively large enzymic forms in serum were correlated with one another and we show they are converted similarly to lower-molecular-mass forms by solubilization with detergents. However, they carry slightly different net charges, thereby ruling out the possibility that they all consisted of a single homogeneous multi-enzyme complex. These findings are discussed in the light of two current hypotheses that the high-molecular-mass enzymes represent (a) membrane fragments released into the circulation in liver disease or (b) low-molecular-mass enzymes that aggregate, after release, with the lipid and protein in the circulation.

High molecular mass kininogen inhibits cathepsin G-induced platelet activation by forming a complex with cathepsin G

2001 ◽  
Vol 2 (6) ◽  
pp. 371-377 ◽  
Author(s):  
Tarek E Selim ◽  
Hayam R Ghoneim ◽  
Hassan A Abdel Ghaffar ◽  
Robert W Colman ◽  
Raul A Dela Cadena
Keyword(s):  
Molecular Mass ◽  
Platelet Activation ◽  
High Molecular Mass ◽  
Cathepsin G

scholarly journals Analysis of High Molecular Mass Compounds from the Spider Pamphobeteus verdolaga Venom Gland. A Transcriptomic and MS ID Approach

Toxins ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 453
Author(s):  
Sebastian Estrada-Gómez ◽  
Leidy Johana Vargas-Muñoz ◽  
Cesar Segura Latorre ◽  
Monica Maria Saldarriaga-Cordoba ◽  
Claudia Marcela Arenas-Gómez
Keyword(s):  
Enzymatic Activity ◽  
Molecular Mass ◽  
Evolutionary Relationship ◽  
Venom Gland ◽  
Duplication Event ◽  
High Molecular Mass ◽  
Amino Acid Sequences ◽  
Secretory Proteins ◽  
Phospholipases A2 ◽  
Kunitz Type

Nowadays, spider venom research focuses on the neurotoxic activity of small peptides. In this study, we investigated high-molecular-mass compounds that have either enzymatic activity or housekeeping functions present in either the venom gland or venom of Pamphobeteus verdolaga. We used proteomic and transcriptomic-assisted approaches to recognize the proteins sequences related to high-molecular-mass compounds present in either venom gland or venom. We report the amino acid sequences (partial or complete) of 45 high-molecular-mass compounds detected by transcriptomics showing similarity to other proteins with either enzymatic activity (i.e., phospholipases A2, kunitz-type, hyaluronidases, and sphingomyelinase D) or housekeeping functions involved in the signaling process, glucanotransferase function, and beta-N-acetylglucosaminidase activity. MS/MS analysis showed fragments exhibiting a resemblance similarity with different sequences detected by transcriptomics corresponding to sphingomyelinase D, hyaluronidase, lycotoxins, cysteine-rich secretory proteins, and kunitz-type serine protease inhibitors, among others. Additionally, we report a probably new protein sequence corresponding to the lycotoxin family detected by transcriptomics. The phylogeny analysis suggested that P. verdolaga includes a basal protein that underwent a duplication event that gave origin to the lycotoxin proteins reported for Lycosa sp. This approach allows proposing an evolutionary relationship of high-molecular-mass proteins among P. verdolaga and other spider species.

Sign in / Sign up

Export Citation Format

Share Document