A new protease in hog thyroid lysosomes

1981 ◽  
Vol 98 (3) ◽  
pp. 390-395 ◽  
Author(s):  
H. Nakagawa ◽  
Y. Endo ◽  
S. Ohtaki
Keyword(s):  
Gel Filtration ◽  
Physiological Role ◽  
Gel Chromatography ◽  
Ph Optimum ◽  
Chloromethyl Ketone ◽  
Protein Substrates ◽  
Liver Lysosomes ◽  
Purification Ratio ◽  
Hydrolysis Of

Abstract. A leupeptin-sensitive new protease was partially purified from hog thyroid lysosomes. The purification procedure included solubilization by hypotonic treatment of lysosomes, and Sephacryl S-300 and Sephadex G-100 gel chromatography, and the purification ratio was 10-fold from lysosomes. The pH optimum of the protease activity was around 5.5 and its molecular weight was estimated to be 22 000 by gel filtration. 2-Mercaptoethanol activated the hydrolysis of protein substrates and its effect was most pronounced in the case of thyroglobulin as substrate. Among the inhibitors used, leupeptin, antipain, toluenesulfonyl-lysine chloromethyl ketone and, to a lesser degree, chymostatin and toluenesulfonyl-phenylalanine chloromethyl ketone effectively inhibited the hydrolysis of casein by the enzyme at pH 5.5, whereas pepstatin did not inhibit the activity significantly. The enzyme activity was also inhibited by sulfhydryl inhibitors such as iodoacetamide, p-chloromercuribenzoate, and N-ethylmaleimide. The release of iodoamino acids from thyroglobulin by the enzyme was inhibited in the same manner by the inhibitors used in the hydrolysis of casein. The physiological role of the new protease is discussed in comparison with cathepsin B and L found in liver lysosomes.

scholarly journals The substrate specificity of acid α-glucosidase from rabbit muscle

1971 ◽  
Vol 124 (4) ◽  
pp. 701-711 ◽  
Author(s):  
T. N. Palmer
Keyword(s):  
Substrate Inhibition ◽  
Physiological Role ◽  
Liver Glycogen ◽  
Rabbit Muscle ◽  
Ph Optimum ◽  
Enzyme Action ◽  
Rate Limiting ◽  
Kinetics Of ◽  
Hydrolysis Of

1. Acid α-glucosidase was purified 3500-fold from rabbit muscle. 2. The enzyme was activated by cations, the degree of activation varying with the substrate. Enzyme action on glycogen was most strongly activated and activation was apparently of a non-competitive type. With rabbit liver glycogen as substrate, the relative Vmax. increased 15-fold, accompanied by an increase in Km from 8.3 to 68.6mm-chain end over the cation range 2–200mm-Na+ at pH4.5. Action on maltose was only moderately activated (1.3-fold, non-competitively) and action on maltotriose was marginally and competitively inhibited. 3. The pH optimum at 2mm-Na+ was 4.5 (maltose) and 5.1 (glycogen). Cation activation of enzyme action on glycogen was markedly pH-dependent. At 200mm-Na+, the pH optimum was 4.8 and activity was maximally stimulated in the range pH4.5–3.3. 4. Glucosidase action on maltosaccharides was associated with pronounced substrate inhibition at concentrations exceeding 5mm. Of the maltosaccharides tested, the enzyme showed a preference for p-nitrophenyl α-maltoside (Km 1.2mm) and maltotriose (Km 1.8mm). The extrapolated Km for enzyme action on maltose was 3.7mm. 5. The macromolecular polysaccharide substrate glycogen differed from linear maltosaccharide substrates in the kinetics of its interaction with the enzyme. Activity was markedly dependent on pH, cation concentration and polysaccharide structure. There was no substrate inhibition. 6. The enzyme exhibited constitutive α-1,6-glucanohydrolase activity. The Km for panose was 20mm. 7. The enzyme catalysed the total conversion of glycogen into glucose. The hydrolysis of α-1,6-linkages was apparently rate-limiting during the hydrolysis of glycogen. 8. Enzyme action on glycogen and maltose released the α-anomer of d-glucose. 9. The results are discussed in terms of the physiological role of acid α-glucosidase in lysosomal glycogen catabolism.

scholarly journals Characterization of the Autocleavage Process of the Escherichia coli HtrA Protein: Implications for its Physiological Role

2008 ◽  
Vol 191 (6) ◽  
pp. 1924-1932 ◽  
Author(s):  
Ahmad Jomaa ◽  
Jack Iwanczyk ◽  
Julie Tran ◽  
Joaquin Ortega
Keyword(s):  
Escherichia Coli ◽  
Physiological Role ◽  
Protein S ◽  
Stress Conditions ◽  
Cage Structure ◽  
Protein Substrates ◽  
Cleavage Process ◽  
Hydrolysis Of

ABSTRACT The Escherichia coli HtrA protein is a periplasmic protease/chaperone that is upregulated under stress conditions. The protease and chaperone activities of HtrA eliminate or refold damaged and unfolded proteins in the bacterial periplasm that are generated upon stress conditions. In the absence of substrates, HtrA oligomerizes into a hexameric cage, but binding of misfolded proteins transforms the hexamers into bigger 12-mer and 24-mer cages that encapsulate the substrates for degradation or refolding. HtrA also undergoes partial degradation as a consequence of self-cleavage of the mature protein, producing short-HtrA protein (s-HtrA). The aim of this study was to examine the physiological role of this self-cleavage process. We found that the only requirement for self-cleavage of HtrA into s-HtrA in vitro was the hydrolysis of protein substrates. In fact, peptides resulting from the hydrolysis of the protein substrates were sufficient to induce autocleavage. However, the continuous presence of full-length substrate delayed the process. In addition, we observed that the hexameric cage structure is required for autocleavage and that s-HtrA accumulates only late in the degradation reaction. These results suggest that self-cleavage occurs when HtrA reassembles back into the resting hexameric structure and peptides resulting from substrate hydrolysis are allosterically stimulating the HtrA proteolytic activity. Our data support a model in which the physiological role of the self-cleavage process is to eliminate the excess of HtrA once the stress conditions cease.

Isolation of specific protease inhibitors from Neurospora crassa

1976 ◽  
Vol 54 (8) ◽  
pp. 699-703 ◽  
Author(s):  
Peter H. Yu ◽  
Maria R. Kula ◽  
Hsin Tsai
Keyword(s):  
Neurospora Crassa ◽  
Protease Inhibitors ◽  
Gel Filtration ◽  
Physiological Role ◽  
Exchange Chromatography ◽  
Proteinase K ◽  
Tryptophan Synthase ◽  
Molecular Weights ◽  
Specific Protease

Four natural protease inhibitors have been partially purified by heat treatment, ion-exchange chromatography and gel filtration from Neurospora crassa. The inhibitory activity has been estimated by measuring the inhibition of proteolysis of casein as well as by the protection of Neurospora tryptophan synthase from proteolytic inactivation. The inhibitors are all oligopeptides and possess molecular weights in the range 5000 – 24 000 and appear to be very specific to Neurospora proteases. They may be classified into two types. The first are specific to Neurospora alkaline protease and the second to acidic protease. None of them exhibited any effect on other proteases including trypsin, chymotrypsin, papain, pepsin, thermolysin, subtilisin and proteinase K. The possible physiological role of these inhibitors is discussed.

scholarly journals Hydrolysis of membrane phospholipids by phospholipases of rat liver lysosomes

1979 ◽  
Vol 182 (2) ◽  
pp. 599-606 ◽  
Author(s):  
Donald E. Richards ◽  
Robin F. Irvine ◽  
Rex M. C. Dawson
Keyword(s):  
Phospholipase C ◽  
Rat Liver ◽  
Lysosomal Enzymes ◽  
Microsomal Fraction ◽  
Water Soluble ◽  
Membrane Phospholipids ◽  
Liver Lysosomes ◽  
Rat Liver Lysosomes ◽  
Hydrolysis Of

(1) The hydrolysis of 32P- or myo-[2-3H]inositol-labelled rat liver microsomal phospholipids by rat liver lysosomal enzymes has been studied. (2) The relative rates of hydrolysis of phospholipids at pH4.5 are: sphingomyelin>phosphatidylethanolamine>phosphatidylcholine> phosphatidylinositol. (3) The predominant products of phosphatidylcholine and phosphatidylethanolamine hydrolysis are their corresponding lyso-compounds, indicating a slow rate of total deacylation. (4) Ca2+ inhibits the hydrolysis of all phospholipids, though only appreciably at high (>5mm) concentration. The hydrolysis of sphingomyelin is considerably less sensitive to Ca2+ than that of glycerophospholipids. (5) Analysis of the water-soluble products of phosphatidylinositol hydrolysis (by using myo-[3H]inositol-labelled microsomal fraction as a substrate) produced evidence that more than 95% of the product is phosphoinositol, which was derived by direct cleavage from phosphatidylinositol, rather than by hydrolysis of glycerophosphoinositol. (6) This production of phosphoinositol, allied with negligible lysophosphatidylinositol formation and a detectable accumulation of diacylglycerol, indicates that lysosomes hydrolyse membrane phosphatidylinositol almost exclusively in a phospholipase C-like manner. (7) Comparisons are drawn between the hydrolysis by lysosomal enzymes of membrane substrates and that of pure phospholipid substrates, and also the possible role of phosphatidylinositol-specific lysosomal phospholipase C in cellular phosphatidylinositol catabolism is discussed.

scholarly journals Genetic Characterization of a Cell Envelope-Associated Proteinase from Lactobacillus helveticus CNRZ32

1999 ◽  
Vol 181 (15) ◽  
pp. 4592-4597 ◽  
Author(s):  
Jeffrey A. Pederson ◽  
Gerald J. Mileski ◽  
Bart C. Weimer ◽  
James L. Steele
Keyword(s):  
Cell Surface ◽  
Deletion Mutant ◽  
Cell Envelope ◽  
Physiological Role ◽  
Lactobacillus Helveticus ◽  
Whole Cells ◽  
A Cell ◽  
Hydrolysis Of

ABSTRACT A cell envelope-associated proteinase gene (prtH) was identified in Lactobacillus helveticus CNRZ32. TheprtH gene encodes a protein of 1,849 amino acids and with a predicted molecular mass of 204 kDa. The deduced amino acid sequence of the prtH product has significant identity (45%) to that of the lactococcal PrtP proteinases. Southern blot analysis indicates thatprtH is not broadly distributed within L. helveticus. A prtH deletion mutant of CNRZ32 was constructed to evaluate the physiological role of PrtH. PrtH is not required for rapid growth or fast acid production in milk by CNRZ32. Cell surface proteinase activity and specificity were determined by hydrolysis of αs1-casein fragment 1-23 by whole cells. A comparison of CNRZ32 and its prtH deletion mutant indicates that CNRZ32 has at least two cell surface proteinases that differ in substrate specificity.

Purification and properties of three endopeptidases from baker's yeast

1989 ◽  
Vol 35 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Jerzy Nowak ◽  
Hsin Tsai
Keyword(s):  
Ethyl Ester ◽  
Baker’S Yeast ◽  
Molecular Forms ◽  
Acid Proteinase ◽  
Baker's Yeast ◽  
Ph Optimum ◽  
Protein Substrates ◽  
Milk Clotting ◽  
Hydrolysis Of ◽  
Milk Clotting Activity

Three endopeptidases, proteinases A, B, and Y, were purified from baker's yeast, Saccharomyces cerevisiae. Two molecular forms of proteinase A (PRA), Mr 45 000 and 54 000, (estimated on SDS-PAGE) were obtained. Both forms were inhibited by pepstatin and other acid proteinase inhibitors. The enzyme digested hemoglobin most rapidly at pH 2.7–3.2 and casein at pH 2.4–2.8 and 5.5–6.0. The optimum pH for hydrolysis of protein substrates could be shifted to about 5 with 4–6 M urea. Urea also stimulated the enzyme activity by 30–50%. As other acid proteinases, the enzyme preferentially cleaved peptide bonds of X–Tyr and X–Phe type. A proteinase B (PRB) preparation of approximately Mr 33 000 possessed milk clotting activity and showed an inhibition pattern typical for seryl-sulfhydryl proteases. The purified enzyme could be stabilized with 40% glycerol and stored at −20 °C without significant loss of activity for several months. The third endopeptidase, designated PRY, of Mr 72 000 when estimated by Sephadex G-100 gel filtration, had properties resembling PRA and PRB. Similar to PRB, it could be inhibited by up to 90% with phenylmethylsulfonyl fluoride and para-chloromercuribenzoate and preferentially hydrolyzed the Leu15–Tyr16 peptide bond of the oxidized β-chain of insulin. On the other hand, contrary to PRB, it had neither milk clotting activity nor esterolytic activity toward N-acetyl-L-tyrosine ethyl ester and N-benzoyl-L-tyrosine ethyl ester and was stable during storage at −20 °C without glycerol. The enzyme also showed a lower pH optimum for hydrolysis of casein yellow than PRB. Similar to PRA, 4 M urea shifted its pH optimum for hydrolysis of protein substrates. PRY degraded apo-aminopeptidase Y much more efficiently than PRB or a PRA–PRB mixture. The possibility of PRY being a precursor form of PRA and PRB is discussed.Key words: yeast, endopeptidase, proteinase, purification.

scholarly journals Purification and characterization of an extracellular (1 → 6)-β-glucanase from the filamentous fungus Acremonium persicinum

1996 ◽  
Vol 316 (3) ◽  
pp. 841-846 ◽  
Author(s):  
Stuart M. PITSON ◽  
Robert J. SEVIOUR ◽  
Barbara M. McDOUGALL ◽  
Bruce A. STONE ◽  
Maruse SADEK
Keyword(s):  
Molecular Mass ◽  
Filamentous Fungus ◽  
Gel Filtration ◽  
Purification And Characterization ◽  
Eisenia Bicyclis ◽  
Ph Optimum ◽  
Hydrolysis Products ◽  
Sds Page ◽  
Hydrolysis Of

An endo-(1 → 6)-β-glucanase has been isolated from the culture filtrates of the filamentous fungus Acremonium persicinum and purified by (NH4)2SO4 precipitation followed by anion-exchange and gel-filtration chromatography. SDS/PAGE of the purified enzyme gave a single band with an apparent molecular mass of 42.7 kDa. The enzyme is a non-glycosylated, monomeric protein with a pI of 4.9 and pH optimum of 5.0. It hydrolysed (1 → 6)-β-glucans (pustulan and lutean), initially yielding a series of (1 → 6)-β-linked oligoglucosides, consistent with endo-hydrolytic action. Final hydrolysis products from these substrates were gentiobiose and gentiotriose, with all products released as β-anomers, indicating that the enzyme acts with retention of configuration. The purified enzyme also hydrolysed Eisenia bicyclis laminarin, liberating glucose, gentiobiose, and a range of larger oligoglucosides, through the apparent hydrolysis of (1 → 6)-β- and some (1 → 3)-β-linkages in this substrate. Km values for pustulan, lutean and laminarin were 1.28, 1.38, and 1.67 mg/ml respectively. The enzyme was inhibited by N-acetylimidazole, N-bromosuccinimide, dicyclohexylcarbodi-imide, Woodward's Regent K, 2-hydroxy-5-nitrobenzyl bromide, KMnO4 and some metal ions, whereas D-glucono-1,5-lactone and EDTA had no effect.

scholarly journals Enzymes of Trichomonas foetus. Separation and properties of two β-galactosidases

1970 ◽  
Vol 117 (4) ◽  
pp. 667-675 ◽  
Author(s):  
G. J. Harrap ◽  
Winifred M. Watkins
Keyword(s):  
Metal Ions ◽  
Gel Filtration ◽  
Galactosidase Activity ◽  
Ph Optimum ◽  
Crude Preparation ◽  
Hydrolysis Of

The β-galactosidase activity in extracts of Trichomonas foetus is separable into two fractions by gel filtration on Sephadex G-200. When o-nitrophenyl β-d-galactoside is used as substrate the first fraction to be eluted, β-galactosidase 1, has 50 times the activity (units per mg of protein) of the crude preparation. This fraction is activated by Mn2+ and Co2+ and inhibited by Hg2+ and EDTA. In the presence of Mn2+ the pH optimum for the hydrolysis of o-nitrophenyl β-d-galactoside or lactose is 5.8–6.0. β-Galactosidase 1 is an exoglycosidase that releases β-linked galactose joined to aliphatic and various carbohydrate aglycones. Hydrolysis is prevented, however, by a substituent on either the subterminal sugar or the terminal non-reducing β-galactosyl residue in an oligosaccharide. The second fraction, β-galactosidase 2, is not activated by metal ions or inhibited by EDTA and has a broad pH optimum from 4.5 to 6.0.

scholarly journals A makro-TSH diagnosztikus és terápiás jelentősége Hashimoto-thyreoiditises betegekben

2017 ◽  
Vol 158 (34) ◽  
pp. 1346-1350
Author(s):  
Csaba Balázs ◽  
Károly †Rácz
Keyword(s):  
Hashimoto’S Thyroiditis ◽  
Screening Method ◽  
Gel Filtration ◽  
Hashimoto's Thyroiditis ◽  
Protein G ◽  
Gel Chromatography ◽  
Clinical Role ◽  
Stimulatory Capacity ◽  
Bio Assay

Abstract: Introduction: Structure, importance and incidence and clinical role of macro-TSH not clarified in thyroid diseases. Aim: This study was undertaken to determine the incidence and biological role of macro-TSH in patients with Hashimoto’s thyroiditis. Method: Blood samples taken from patients with Hashimoto’s thyroiditis were screened for the presence of macro-TSH with the polyethylene glycol method and confirmed with protein G agarose absorption test and gel filtration chromatography. Stimulatory capacity of macro-TSH was measured by CHO cells bio-assay. Patients were treated with L-thyroxine (mean 66.5 µg/day) and half of them with selenium (mean 60 µg/day), respectively. Results: 880 patients (728 female, aged 44.8 yr) with Hashimoto’s thyroiditis was involved in the study. Macro-TSH was found in the serum of 41 patients (4.6%), the mean TSH 185.4 ± 35 IU/l was before PEG precipitations and after 5.55 ± 1.8 IU/l. Titre of anti-TPO proved to be 445 ± 51 IU/l and gradulally decreased to 212 ± 51 IU/l after one year therapy. Both the precipitation, protein G absorption and gel chromatography supported the presence of anti-TSH antibody in the macro-TSH complex. Stimulatory capacity of macro-TSH on CHO bio-assay was not proved. The macro-TSH was detected in the selenium not treated group for 18 ± 3.2 months, selenium-treated for 12 ± 1.9 months. Conclusion: It is concluded that anti-human TSH autoantibodies are a major components of macro-TSH and may cause diagnostic and therapeutical difficulties. The PEG precipitation is a suitable screening method for detection of macro-TSH. Selenium is able to decrease of anti-TPO antibodies and macro-TSH, respectively. When the TSH level is greater than 40.0 IU/l, without the signs of hypothyroidism, the presence of macro-TSH is to be considered. Orv Hetil. 2017; 158(34): 1346–1350.

scholarly journals Purification and properties of a 1,3-1,4-β-d-glucanase (lichenase, 1,3-1,4-β-d-glucan 4-glucanohydrolase, EC 3.2.1.73) from Bacteroides succinogenes cloned in Escherichia coli

1988 ◽  
Vol 255 (3) ◽  
pp. 833-841 ◽  
Author(s):  
J D Erfle ◽  
R M Teather ◽  
P J Wood ◽  
J E Irvin
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Gel Filtration ◽  
Maximum Activity ◽  
Temperature Optimum ◽  
Glucanase Activity ◽  
Ph Optimum ◽  
Beta Glucanase ◽  
Purification And Properties ◽  
Hydrolysis Of

A 1,3-1,4-beta-D-glucanase (lichenase, 1,3-1,4-beta-D-glucan 4-glucanohydrolase, EC 3.2.1.73) from Bacteroides succinogenes cloned in Escherichia coli was purified 600-fold by chromatography on Q-Sepharose and hydroxyapatite. The cloned enzyme hydrolysed lichenin and oat beta-D-glucan but not starch, CM(carboxymethyl)-cellulose, CM-pachyman, laminarin or xylan. The enzyme had a broad pH optimum with maximum activity at approx. pH 6.0 and a temperature optimum of 50 degrees C. The pH of elution from a chromatofocusing column for the cloned enzyme was 4.7 (purified) and 4.9 (crude) compared with 4.8 for the mixed-linkage beta-D-glucanase activity in B. succinogenes. The Mr of the cloned enzyme was estimated to be 37,200 by gel filtration and 35,200 by electrophoresis. The Km values estimated for lichenin and oat beta-D-glucan were 0.35 and 0.71 mg/ml respectively. The major hydrolytic products with lichenin as substrate were a trisaccharide (82%) and a pentasaccharide (9.5%). Hydrolysis of oat beta-D-glucan yielded a trisaccharide (63.5%) and a tetrasaccharide (29.6%) as the major products. The chromatographic patterns of the products from the cloned enzyme appear to be similar to those reported for the mixed-linkage beta-D-glucanase isolated from Bacillus subtilis. The data presented illustrate the similarity in properties of the cloned mixed-linkage enzyme and the 1,3-1,4-beta-D-glucanase from B. subtilis and the similarity with the 1,4-beta-glucanase in B. succinogenes.

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