Anti‐histone H1 IgGs from blood serum of systemic lupus erythematosus patients are capable of hydrolyzing histone H1 and myelin basic protein

Novel hydrolytic activity of the anti‐histone H1 antibodies (Ab) toward histone H1 and myelin basic protein (MBP) was shown. Blood serum of ten patients with clinically diagnosed systemic lupus erythematosus (SLE), and nine healthy donors (control) were screened for the anti‐histone H1 antibody‐ and anti‐MBP antibody‐mediated specific proteolytic activity. IgGs were isolated by chromatography on Protein G‐Sepharose, and four of ten SLE patients appeared to possess IgGs that were capable of cleaving both histone H1 and MBP. Such activity was confirmed to be an intrinsic property of the IgG molecule, since it was preserved at gel filtration at alkaline and acidic pH. At the same time, proteolytic activity was absent in the sera‐derived Ab of all healthy donors under control. Anti‐histone IgGs were purified by the affinity chromatography on histone H1‐Sepharose. Their cross‐reactivity toward cationic proteins (histones, lysozyme, and MBP) and their capability of hydrolyzing histone H1 and MBP were detected. However, these IgGs were not cleaving core histones, lysozyme, or albumin. Capability of cleaving histone H1 and MBP was preserved after additional purification of anti‐histone H1 IgGs by the HPLC gel filtration. The protease activity of anti‐histone H1 IgG Ab was inhibited by serine protease inhibitors. Copyright © 2010 John Wiley & Sons, Ltd.     

Protease from a strain of bacteria E. coli A2, specifically cleaving actin

A novel bacterial protease specifically hydrolyzing actin with the formation of a stable fragment with Mr of 36 kDa was obtained. This protease was shown to be synthesized at the stationary phase of bacterial culture growth. The actin hydrolysis by bacterial protease was inhibited by o-phenanthroline, EDTA and p-chloromercuribenzoate but not by N-ethyl-maleimide, phenylmethylsulfonylfluoride, Leu-peptin, pepstatin and other serine proteinase inhibitors. The protease was stable within the pH range of 4.5-8.5 and had an activity optimum at pH 7.0-8.0. The protease activity was maintained for 40 min at 45 degrees C and for 30 min at 50 degrees C; at 65 degrees C the enzyme was fully inactivated by 5 min heating. The protease preparations causing quantitative conversion of actin into a 36 kDa fragment did not hydrolyze casein, albumin, ovalbumin, lysozyme, DNAase I, RNAase, myosin, alpha-actinin, tropomyosin and troponin. It was assumed that the protease under consideration is a neutral metalloprotease specifically hydrolyzing actin.     

Calcium activated proteolysis of fibrous proteins in central nervous system

A Ca²⁺ activated protease(s) capable of hydrolyzing several polypeptides at neutral pH including cytoskeletal proteins, actin, myosin, tubulin and neurofilament triplet was identified in calf brain cortex. The enzyme activity precipitates at 75 mM KCl, pH 6.5 – 7.0 and is inhibited by the sulfhydryl inhibitors, N-ethylmaleimide and para-chloromercuribenzoate and the protease inhibitors, antipain, pepstatin and leupeptin, leupeptin being the most effective.     

Influence of bioprocess variables on the production of extracellular chitinase under submerged fermentation by Streptomyces pratensis strain KLSL55

Chitinases are the enzymes which are capable of hydrolyzing chitin to its monomer N-acetyl glucosamine (GlcNac). Present study emphasizes on the impact of critical process variables on the production of chitinase from Streptomyces pratensis strain KLSL55. Initially the isolate was noticed to produce 84.67?IU chitinase in basal production medium. At optimization of bioprocess variables, the physical parameters pH of 8.00, 40?°C of incubation temperature, agitation speed of 160?rpm and 1.25?mL of spore suspension were found optimum for improved production of chitinase. Further, formulated production medium with 1.5% colloidal chitin, 1.25% fructose greatly influenced the chitinase production. At all described optimum conditions with formulated production media, a total of 14.30-fold increment was achieved in the chitinase production with final activity of 1210.67?IU when compared to the initial fermentation conditions in basal production medium.     

Detection and characterization of IgG-and sIgA-abzymes capable of hydrolyzing histone H1

Immunoglobulins IgG and sIgA actively hydrolyzing histone H1 have been detected on analyzing proteolytic activity of antibodies isolated by chromatography on Protein A-agarose from blood serum of patients with multiple sclerosis and from colostrum of healthy mothers. These antibodies hydrolyze other histones less actively and virtually failed to cleave lysozyme of chicken egg. By gel filtration at acidic pH and subsequent analysis of protease activity of chromatographic fractions, it was shown that IgG and sIgA molecules were responsible for hydrolysis of histone H1. Anti-histone H1 antibodies of IgG and sIgA classes were purified by affinity chromatography on histone H1-Sepharose from catalytically active antibody preparations. The protease activity of anti-histone H1 IgG antibodies was inhibited by serine proteinase inhibitors, whereas anti-histone H1 sIgA antibodies were insensitive to inhibitors of serine, asparagine, and cysteine proteases.     

Partial purification of two distinct enkephalin-degrading aminopeptidases from human cerebrospinal fluid

In human cerebrospinal fluid, aminopeptidase, dipeptidyl aminopeptidase, dipeptidyl carboxypeptidase, and carboxypeptidase which were capable of hydrolyzing enkephalins were detected. Among these enzymes, two distinct aminopeptidase, designated C-AP1 and C-AP2, were partially purified. These enzymes were not purified thoroughly, but the characteristics of C-AP2 were similar to those of an aminopeptidase purified from monkey brain. But the inhibitory activity of amastatin on C-AP2 was stronger, and that of substance P was negligible. On the other hand, characteristics of C-Ap1 were extremely differ from those of C-AP2 or an aminopeptidase purified from monkey brain. C-AP1 had an optimum pH more in the acidic range (the highest at pH 6.0) and was not inhibited by any of the protease inhibitor tested including bestatin and amastatin.     

Evaluation of the CFP-substrate-YFP system for protease studies: advantages and limitations

A protease can be defined as an enzyme capable of hydrolyzing peptide bonds. Thus, characterization of a protease involves identification of target peptide sequences, measurement of activities toward these sequences, and determination of kinetic parameters. Biological protease substrates based on fluorescent protein pairs, which allow for use of fluorescence resonance energy transfer (FRET), have been recently developed for in vivo protease activity detection and represent a very interesting alternative to chemical substrates for in vitro protease characterization. Here, we analyze a FRET system consisting of cyan and yellow fluorescent proteins (CFP and YFP, respectively), which are fused by a peptide linker serving as protease substrate. Conditions for CFP-YFP fusion protein production in Escherichia coli and purification of proteins were optimized. FRET between CFP and YFP was found to be optimum at a pH between 5.5 and 10.0, at low concentrations of salt and a temperature superior to 25 degrees C. For efficient FRET to occur, the peptide linker between CFP and YFP can measure up to 25 amino acids. The CFP-substrate-YFP system demonstrated a high degree of resistance to nonspecific proteolysis, making it suitable for enzyme kinetic analysis. As with chemical substrates, substrate specificity of CFP-substrate-YFP proteins was tested towards different proteases and kcat/Km values were calculated.     

Studies on Aspergillus Fumigatus; Hydrolysis of Polyamino Acids by Mycelial Filtrate and Chromatographic Fractionation of the Filtrate

Mycelial filtrates from Aspergillus fumigatus (AF), shown to possess haemolytic, toxic, casein precipitating, and protein hydrolyzing activity, hydrolyzed poly-L-lysine and poly-L-glutamine in the pH range 4.6—5.3. Incipient activity against poly-L-lysin was observed at pH 9. Owing to spontaneous hydrolysis of the polyamino acid at pH > 10, no activity optimum could be traced. Gel filtration of mycelial filtrate on Sephadex G-75 or G-100 columns offered no definite information whether the protein hydrolyzing activity, using haemoglobin as substrate, at the optimum pH values, 2.9, 4.6 and 10, shows the activity of a single enzyme with more than 1 pH optimum or of more than 1 enzyme active at different pH values. Certain results of the investigations seem to indicate that the protein hydrolyzing activity at pH 2.9 was not caused by enzymes identical with the enzyme (s) causing the protein hydrolyzing activity at pH 4.6 or pH 10. Casein precipitating and protein hydrolyzing activity occurred, following gel filtration on a Sephadex G-100 column, in identical fractions whereas neither haemolysin nor toxin could be found in samples of 0.5 ml fraction solution from any of the fractions after filtration on Sephadex G-75 or G-100 columns. By using antiserum to a crude filtrate from a homologous AF strain it could be shown, applying immuno-electrophoresis, that dialyzed mycelial filtrate contained 8 precipitating antigens whereas proteinase purified by gel filtration and displaying protein hydrolyzing activity at pH 2.9, pH 4.6 and pH 10 contained 4 such antigens.     

A protease activity is associated with testicular chromatin of the mouse

A protease activity associated with the micrococcal nuclease-solubilized chromatin from mouse seminiferous tubules has been characterized. Proteolysis of histone H1 and core histones is stimulated in the presence of 3 M urea. The pH optimum of this protease is between pH 8 and 9, and the activity is not inhibited by trypsin or chymotrypsin-active site inhibitors. Leupeptin is an effective inhibitor of the protease at low concentrations. Soluble chromatin from neonatal and prepubertal mice lacks this proteolytic activity until three to four weeks after birth. That the protease activity is localized in the dinucleosomes and higher oligomers but is lacking in mononucleosome populations suggests its association with the linker DNA. Rat testis-soluble chromatin apparently lacks such a protease activity. The developmental expression of this protease and its in situ localization are consistent with a role in histone displacement during mouse spermiogenesis.     

Purification and properties of a new aminopeptidase from Escherichia COLI K12.

An aminopeptidase (EC 3.4.11.-) capmable of hydrolyzing L-alanyl-beta-naphthyl-amide and certain other aminoacyl beta-naphthylamides was purified to homogeneity from extracts of Exherichia coli K-12. The enzyme, designated aminopeptidase II, is a monomeric protein of mol. wt. 100 000. It exhibits a broad pH optimum in the range pH 7.0--9.0. Although Zn2+, Fe3+ and Cr3+ are strong inhibitors of enzyme activity, a metal requirement for catalysis could not be firmly established. Neither sulfhydryl reagents nor serine protease inhibitors affected enzyme activity.     

Production of an extracellular alkaline metalloprotease from a newly isolated, moderately halophile, Salinivibrio sp. strain AF-2004

An extracellular protease was produced under stress conditions of high temperature and high salinity by a newly isolated moderate halophile, Salinivibrio sp. strain AF-2004 in a basal medium containing peptone, beef extract, glucose and NaCl. A modification of Kunitz method was used for protease assay. The isolate was capable of producing protease in the presence of sodium chloride, sodium sulfate, sodium nitrate, sodium nitrite, potassium chloride, sodium acetate and sodium citrate. The maximum protease was secreted in the presence of 7.5 to 10% (w/v) sodium sulfate or 3% (w/v) sodium acetate (4.6 U ml⁻¹). Various carbon sources including glucose, lactose, casein and peptone were capable of inducing enzyme production. The optimum pH, temperature and aeration for enzyme production were 9.0, 32 °C and 220 rpm, respectively. The enzyme production corresponded with growth and reached a maximum level during the mid-stationary phase. Maximum protease activity was exhibited in the medium containing 1% (w/v) NaCl at 60 °C, with 18% and 41% activity reductions at temperature 50 and 70 °C, respectively. The optimum pH for enzyme activity was 8.5, with 86% and 75% residual activities at pH 10 and 6, respectively. The activity of enzyme was inhibited by EDTA. These results suggest that the protease secreted by Salinivibrio sp. strain AF-2004 is industrially important from the perspectives of its activity at a broad pH ranges (5.0–10.0), its moderate thermoactivity in addition to its high tolerance to a wide range of salt concentration (0–10% NaCl).     

Characterization of the carboxypeptidase N secreted by Hep G2 cells

Human hepatoma (Hep G2) cells secrete nanogram quantities of carboxypeptidase enzymes which are capable of hydrolyzing COOH-terminal lysine and arginine residues. A carboxypeptidase with a neutral pH optimum (greater than pH 7.0) was partially purified from the conditioned medium and compared with pure plasma carboxypeptidase N. The two enzymes behaved in a similar manner on gel filtration (apparent Mr = 280,000), DE52 ion exchange chromatography, and concanavalin A-affinity chromatography and were indistinguishable enzymatically and immunologically. Immunoblots of the Hep G2 and plasma carboxypeptidase N before and following deglycosylation with peptide-N4-[N-acetyl-beta-glucosaminyl]asparagine amidase F revealed a similar, if not identical, multimeric structure. A second carboxypeptidase with a lower molecular weight and a pH optimum of 5.0 was also detected in the Hep G2 medium.     

Purification and Characterization,of Rice Bran Lipase II

A species of rice bran lipase (lipase II) was purified by ammonium sulfate precipitation, followed by successive chromatographies on DEAE-cellulose, Sephadex G–75 and CH-Sephadex C–50. Both polyacrylamide disc electrophoresis and ultracentrifugation demonstrated that the enzyme protein is homogeneous. The isoelectric point of the enzyme was 9.10 by ampholine electrophoresis. The sedimentation coefficient of the enzyme was evaluated to be 2.60 S, and the molecular weight to be 33,300 according to Archbald’s method. The enzyme showed the optimum pH between 7.5 and 8.0, and the optimum temperature at about 27°C. It was stable over the pH range from 5 to 9.5 and below 30°C. In substrate specificity, the enzyme exhibited a high specificity toward triglycerides having short-carbon chain fatty acids, although it was capable of hydrolyzing the ester bonds in the rice and olive oil.     

Enzymatic Properties of Rice Bran Lipase

The enzyme showed the optimum pH between 7.5 and 8.0, and the optimum temperature at about 37°C. It was stable over the pH range from 4 to 9 and below 40°C, but completely lost the activity by heating 60°C for 15 min. The enzyme was activated by low concentration of calcium ion but inhibited partially by high concentration of calcium ion and by EDTA. With respect to substrate specificity, the enzyme exhibited a high specificity toward triglycerides and hydrolyzed ester bonds of short-carbon chain triglycerides faster than long-carbon chain triglycerides, whereas it catalyzed the hydrolysis of the oils from rice bran, olive and coconut. When 2-oleo-1,3-distearin was used as substrate, the enzyme was capable of preferentially hydrolyzing fatty acid ester bonds at the 1,3-position.     

Substrate specificity and kinetic properties of a soluble nucleoside triphosphatase from bovine kidneys

Soluble nucleoside triphosphatase differing in its properties from all known proteins with NTPase activity was partially purified from bovine kidneys. The enzyme has pH optimum of 7.5, molecular mass of 60 kDa, as estimated by gel chromatography, and shows an absolute dependence on divalent metal ions. NTPase obeyed Michaelis-Menten kinetics in the range of substrate concentration tested from 45 to 440 microM; the apparent Km for inosine-5'-triphosphate was calculated to be 23.3 microM. The enzyme was found to possess a broad substrate specificity, being capable of hydrolyzing various nucleoside-5'-tri- as well as diphosphates.     

Preparation of immobilized enzymes by N-vinylpyrrolidone and the general properties of the glucoamylase gel

Immobilized glucoamylase, invertase, and β-galactosidase were prepared by using N-vinylpyrrolidone monomer (VP) under γ-ray irradiation. The enzyme-VP solutions were gelled by irradiation with 2.9 Mrad and the added enzymes were almost completely entrapped. Activity losses on entrapping were 55% for the VP-glucoamylase gel, and more than 90% in the case of VP-invertase and VP-β-galactosidase gels. No leakage of enzyme from these gels could be detected within 1 hr. The VP-glucoamylase gel was capable of hydrolyzing dextrin (mol wt 10,400) to glucose and the glucose equivalent was equal to that obtain able with native enzyme. The optimum temperature, heat stability, pH activity curve, and pH stability of VP-glucoamylase gel were slightly inferior to those of native enzyme, while Km was a little larger than that of native enzyme.     

Nutritional factors affecting organic solvent-tolerant alkaline protease production by a newBacillus cereus strain 146

An organic solvent-tolerant bacterium designated as 146 capable of producing an organic solvent-stable alkaline protease was isolated from contaminated soil of a wood factory. The strain was a Gram-positive, spore-forming, nitrate-positive, rod-shaped organism capable of hydrolysing gelatine, starch, skim milk and identified asBacillus cereus. Activity of the protease was drastically increased in the presence of 1–decanol, isooctane, n-dodecane and n-tetradecane, but reduced in the presence of ethyl acetate, benzene, toluene, 1-heptanol, ethylbenzene and hexane. The bacterium was shown to require lactose as a carbon source and peptone as a nitrogen source. The optimum fermentation condition for the production of alkaline protease was in the presence of beef and yeast extract. Optimum pH was determined to be at 10.0 at incubation temperature of 37 °C for 48 h. Results from the studies suggest that 146 is a new strain of Bacillus cereus capable of producing organic solvent-tolerant alkaline protease with potential use in industries.     

Enzymatic properties of a novel highly active and chelator resistant protease from a Pseudomonas aeruginosa PD100

Pseudomonas aeruginosa PD100 capable of producing an extracellular protease was isolated from the soil collected from local area (garbage site) from Shivage market in Pune, India. The purified protease showed a single band on native and SDS-PAGE with a molecular weight of 36 kDa on SDS-PAGE. The optimum pH value and temperature range were found to be 8 and 55–60 °C, respectively. The enzyme exhibited broad range of substrate specificity with higher activity for collagen. The enzyme was inhibited with low concentration of Ag²⁺, Ni²⁺, and Cu²⁺. β-Mercaptoethanol was able to inactivate the enzyme at 2.5 mM, suggesting that disulfide bond(s) play a critical role in the enzyme activity. Studies with inhibitors showed that different classes of protease inhibitors, known to inhibit specific proteases, could not inhibit the activity of this protease. Amino acid modification studies data and pK_a values showed that Cys, His and Trp were involved in the protease activity. P. aeruginosa PD100 produces one form of protease with some different properties as compared to other reported proteases from P. aeruginosa strains. With respect to properties of the purified protease such as pH optimum, temperature stability with capability to degrade different proteins, high stability in the presences of detergents and chemicals, and metal ions independency, suggesting that it has great potential for different applications.     

Production of an alkaline protease using Bacillus pumilus D3 without inactivation by SDS,its characterization and purification

Abstract

In this study, protease-producing capacity of Bacillus pumilus D3, isolated from hydrocarbon contaminated soil, was evaluated and optimized. Optimum growing conditions for B. pumilus D3 in terms of protease production were determined as 1% optimum inoculum size, 35?°C temperature, 11 pH and 48?h incubation time, respectively. Stability studies indicated that the mentioned protease was stable within the pH range of 7–10.5 and between 30?°C and 40?°C temperatures. Surprisingly, the activity of the enzyme increased in the presence of SDS with concentration up to 5?mM. The protease was concentrated 1.6-fold with ammonium sulfate precipitation and dialysis. At least six protein bands were obtained from dialysate by electrophoresis. Four clear protein bands with caseinolytic activity were detected by zymography. Dialysate was further purified by anion-exchange chromatography and the caseinolytic active fraction showed a single band between 29 and 36?kDa of reducing conditions.     

Purification and characterization of an extracellular protease from the fish pathogen Yersinia ruckeri and effect of culture conditions on production.

A novel protease, hydrolyzing azocasein, was identified, purified, and characterized from the culture supernatant of the fish pathogen Yersinia ruckeri. Exoprotease production was detected at the end of the exponential growth phase and was temperature dependent. Activity was detected in peptone but not in Casamino Acid medium. Its synthesis appeared to be under catabolite repression and ammonium control. The protease was purified in a simple two-step procedure involving ammonium sulfate precipitation and ion-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified protein indicated an estimated molecular mass of 47 kDa. The protease had characteristics of a cold-adapted protein, i.e., it was more active in the range of 25 to 42 degrees C and had an optimum activity at 37 degrees C. The activation energy for the hydrolysis of azocasein was determined to be 15.53 kcal/mol, and the enzyme showed a rapid decrease in activity at 42 degrees C. The enzyme had an optimum pH of around 8. Characterization of the protease showed that it required certain cations such as Mg(2+) or Ca(2+) for maximal activity and was inhibited by EDTA, 1,10-phenanthroline, and EGTA but not by phenylmethylsulfonyl fluoride. Two N-methyl-N-nitro-N-nitrosoguanidine mutants were isolated and analyzed; one did not show caseinolytic activity and lacked the 47-kDa protein, while the other was hyperproteolytic and produced increased amounts of the 47-kDa protein. Azocasein activity, SDS-PAGE, immunoblotting by using polyclonal anti-47-kDa-protease serum, and zymogram analyses showed that protease activity was present in 8 of 14 strains tested and that two Y. ruckeri groups could be established based on the presence or absence of the 47-kDa protease.