The cellulase of Fusarium solani. Resolution of the enzyme complex

1. Culture filtrates from Fusarium solani were fractionated by ion-exchange chromatography on DEAE-Sephadex, followed by gel chromatography on Sephadex G-100, into a C(1) component, a C(x) component (CM-cellulase) and a beta-glucosidase (cellobiase) component. 2. The individual components showed little capacity for the solubilization of cotton fibre (cellulase activity), but when recombined in their original proportions 81% of the original cellulase activity was recovered. 3. The C(1) components of F. solani and Trichoderma koningii were similar in their pH optima, heat stabilities over the pH range 5-8 and elution volumes on Sephadex G-100. 4. The C(1) component of F. solani synergized with the C(x) component of T. koningii and conversely. 5. The C(1) and the beta-glucosidase components of F. solani were devoid of the swelling-factor (S-factor) activity associated with the C(x) component.     

The purification and properties of microsomal palmitoyl-coenzyme A synthetase

1. Cell-free culture filtrates of the fungus Fusarium solani were examined for homogeneity with respect to beta-d-glucosidase and C(x) activities. 2. o-Nitrophenyl beta-d-glucoside and cellobiose were both used as substrates for beta-d-glucosidase activity. 3. No evidence for the non-identity of nitrophenyl beta-d-glucosidase and cellobiase activities could be found, either by heat treatment, gel filtration on Sephadex G-100 or by isoelectric focusing. 4. The beta-d-glucosidase component was also a feeble exo-beta-glucanase: it had a molecular weight of approx. 400000. 5. The fall in viscosity of a solution of CM-cellulose, the formation of reducing sugars in a solution of CM-cellulose and the solubilization of phosphoric acid-swollen cellulose (Walseth cellulose), were all used for the measurement of C(x) activity. 6. The ratio of the two types of CM-cellulase activity was not changed after gel filtration on Sephadex G-100 or after chromatography on DEAE-Sephadex. 7. Three peaks of C(x) activity were obtained after electrofocusing, but all three possessed the same ratio of the two types of CM-cellulase activity as well as the same CM-cellulase/Walseth activity ratio, as the unfractionated enzyme; all three isoenzymes (isoelectric points, 4.75, 4.80-4.85 and 5.15) acted in synergism with a mixture of the C(1) and the beta-d-glucosidase components to the same extent in the solubilization of cotton fibre. 8. The molecular weight of the C(x) component was approx. 37000.     

The formation of short fibres from native cellulose by components of Trichoderma koningii cellulase

Cellulolytic enzyme components of culture filtrates of Trichoderma koningii were fractionated on ionic and non-ionic forms of Sephadex and on cellulose powder (Whatman) and examined for their ability to hydrolyse soluble carboxymethyl-cellulose, and to saccharify, solubilize and form short fibres from native undegraded cellulose of the type found in cotton. DEAE-Sephadex provided two CM-cellulase components and a C(1) component; the C(1) component acted weakly and solely on cotton, forming soluble products but not short fibres. The ability to form short fibres was confined almost wholly to one of the CM-cellulase components which completely degraded cotton, minimally to soluble products and extensively to short fibres. The latter action was unaffected by the presence of the other two components. The two CM-cellulase components solubilized cellulose synergistically whereas the short-fibre-forming component and C(1) component were inhibitory.     

The purification and properties of the C1 component of Trichoderma koningii cellulase

1. The C(1) component that was isolated from a Trichoderma koningii cellulase preparation (Wood, 1968) by chromatography on DEAE-Sephadex with a salt gradient was still associated with a trace of CM-cellulase activity (determined by reducing-sugar and viscometric methods). 2. Further chromatography on DEAE-Sephadex, with a pH gradient instead of a salt gradient, provided a C(1) component that could still produce reducing sugars from a solution of CM-cellulose (to a very limited extent), but which could no longer decrease the viscosity (i.e. under the assay conditions employed). 3. No evidence for the non-identity of C(1) component and the trace of CM-cellulase activity could be found when electrofocusing was done in a stabilized pH gradient covering three pH units (pH3-6) or, alternatively, only 0.5 pH unit (pH3.72-4.25). 4. The two protein peaks that were separated by electrofocusing in carrier ampholytes covering only 0.5 pH unit (isoelectric pH values of 3.80 and 3.95) were shown to be isoenzymes of the C(1) component: they differed in the extent to which they were associated with carbohydrate (9% and 33%). 5. The purified C(1) component had little ability to attack CM-cellulose or highly ordered forms of cellulose, but degraded phosphoric acid-swollen cellulose readily: cellobiose was the principal product of the hydrolysis (97%). 6. Dewaxed cotton fibre was degraded to the extent of 15% when exposed to high concentrations of C(1) component over a prolonged period: cellobiose was again the principal sugar present in the supernatant (96%). 7. Cellotetraose and cellohexaose were hydrolysed almost exclusively to cellobiose. 8. Evidence indicates that the C(1) component is a beta-1,4-glucan cellobiosylhydrolase.     

The cellulase of Trichoderma viride: Separation of the components involved in the solubilization of cotton

1. Culture filtrates from Trichoderma viride have been fractionated by gel filtration on Sephadex G-75 followed by ion-exchange chromatography on DEAE- and SE-Sephadex. 2. The components essential for attack on cotton are a carboxymethylcellulase, a cellobiase and a third (C₁) component which has no action on CM-cellulose, cellobiose or cotton. 3. These components, which together can completely convert cotton into water-soluble products, lose this ability when separated and regain it quantitatively when recombined in their original proportions.     

Identity of `acid'' β-glucosidase and glucocerebrosidase in human spleen

1. Glucocerebrosidase, in association with a membrane-bound ;acid' beta-glucosidase, was separated from a soluble ;neutral' beta-glucosidase that had no activity towards glucocerebroside as substrate. 2. Glucocerebrosidase, as well as ;acid' beta-glucosidase activity depended upon the association of factor P (a heat-stable, soluble, acidic glycoprotein) with factor C (a heat-labile membrane-bound protein). 3. Factor C was solubilized under certain conditions. 4. Solubilized factor C, as well as membrane-bound factor C, could be alternatively stimulated by sodium taurocholate to give both glucocerebrosidase and ;acid' beta-glucosidase activities. 5. Membrane-bound factor C reacted optimally with factor P whereas solubilized factor C was preferentially stimulated by taurocholate. 6. Factor P-dependent glucocerebrosidase activity differed in kinetic properties from the taurocholate-stimulated enzyme activity. 7. The results are discussed in the light of (a) identity of glucocerebrosidase and ;acid' beta-glucosidase, (b) application in clinical diagnosis, (c) physiological significance of the enzyme system, and (d) polygenic inheritance in adult Gaucher's disease.     

Interactions between components of the cellulase complex of Trichoderma koningii on native substrates

Summary The cellulase complex of Trichoderma koningii has been separated into four apparently pure components namely cellobiase, a C₁-like component and two new components, one a CM-cellulase, the other named component C₂. All four are necessary for efficient solubilisation of native cellulose. 2. The two new components together constitute the composite CM-cellulase-short-fibre forming activity described by Halliwell and Riaz (1970). 3. Alone only components C₂ and C₁ have any action on the substrate, the former being somewhat more effective than the C₁ component which shows weak solubilising power. 4. Component C₂ degrades cellulose weakly to short-fibres but synergises extensively with the CM-cellulase in promoting this process. In contrast the CM-cellula se fails to react significantly with component C₁. 6. The interaction of all four components in contributing to the degradation of native cellulose is discussed.     

Isolation and structure of a tryptic glycopeptide from the active site of beta-glucosidase A3 from Aspergillus wentii

An electrophoretic system using cellulose acetate has been developed for the resolution of beta-glucosidase isozymes (beta-D-glucoside glucohydrolase, EC 3.2.1.21 and D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45) in human tissue homogenates. Electrophoresis of homogenates from normal and Type 1 Gaucher disease tissues revealed two fluorescent bands of beta-glucosidase activity which corresponded to the acid and neutral isozymes separated by concanavalin A-Sepharose chromatography. The acid isozyme has only beta-glucosidase activity, whereas the neutral isozyme also exhibited alpha-L-arabinosidase (alpha-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55), beta-D-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) and beta-D-xylosidase (1,4-beta-D-xylan xylohydrolase, EC 3.2.1.37) activities, using the appropriate 4-methylumbelliferyl glycoside. In homogenates of cultured skin fibroblasts, only the acid isozyme was observed which co-electrophoresed with the acidic activity in other tissue homogenates. The acidic activity in tissue and fibroblast homogenates from Type 1 Gaucher disease appeared to co-electrophorese with the acid isozyme in normal tissues, but had markedly reduced activity.     

Purification and characterization of cellulolytic enzymes fromTrichoderma harzianum

Two forms of filter paper activity (filter paper activity; cellulose 1,4-β-cellobiosidase, EC 3.2.1.91) and single forms of CM-cellulase (carboxymethyl cellulase; endo-l,4-β-glucanase, EC 3.2.1.4) and β-glucosidase (β-D-glucoside glucohydrolase, EC 3.2.1.21) from the culture filtrate ofTrichoderma harzianum were separated and partially purified by (NH₄)₂SO₄ precipitation, ion-exchange chromatography and gel filtration. The final preparation was purified about 12-, 20- and 27-fold for FP-activity, CM-oellulase and β-glueosidase, respectively. The pH and temperature optima, stability, kinetic parameters, effeet of metal ions and molar mass of each was determined. A distinct type of synergistic action between cellulase components was observed for efficientin vitro saccharification of dewaxed cotton.     

Identification and purification of the main components of cellulases from a mutant strain of Trichoderma viride T 100-14

A new mutant strain of fungus Trichoderma viride T 100-14 was cultivated on 1% microcrystalline cellulose (Avicel) for 120h and the resulting culture filtrate was prepared for protein identification and purification. To identify the predominant catalytic components, cellulases were separated by an adapted two-dimensional electrophoresis technique. The apparent major spots were identified by high performance liquid chromatography electrospray ionization mass (HPLC-ESI-MS). Seven of the components were previously known, i.e., the endoglucanases Cel7B (EG I), Cel12A (EG III), Cel61A (EG IV), the cellobiohydrolases Cel7A (CBH I), Cel6A (CBH II), Cel6B (CBH IIb) and the beta-glucosidase. The seven major components in the fermentation broth of T. viride T 100-14 probably constitute the essential enzymes for crystalline cellulose hydrolysis and they were further purified to electrophoretic homogeneity by a series of chromatography column. Hydrolysis studies of the purified elements revealed that three of the cellulases were classified as cellobiohydrolases due to their main activities on p-nitrophenyl-beta-d-cellobioside (pNPC). Three of the cellulases, with the abilities of hydrolyzing both carboxymethyl-cellulose (CMC) and Avicel indicate their endoglucanase activities. It deserved noting that the beta-glucosidase from the T 100-14 displayed an extremely high activity on p-nitrophenyl-beta-D-glycopyranoside (pNPG), which suggested it was a good candidate for the conversion of cellobiose to glucose.     

THE N-ACETYL-β-d-HEXOSAMINIDASES OF CALF AND HUMAN BRAIN

Abstract— Multiple forms of calf brain N -acetyl-β-hexosaminidases (β-2-acetamido-2- deoxy- d -glucoside acetamidodeoxyglucohydrolase EC 3.2.1.30) were separated on starch gel electrophoresis at pH 5.8. The organ specific electrophoretic patterns did not depend on the cell fraction studied. Much of the activity is only separated with difficulty from particulate matter. Two major and one minor component were separated on DEAE-cellulose chromatography at pH 5.8. Each component had both N -acetyl-β-galactosaminidase and N -acetyl-β-glucosaminidase activity. The ratio of these two activities was unaffected by the presence of N -ethylmaleimide or dithiothreitol. The forms were also examined by isoelectric focusing when at least four components were recognized: isoelectric at 4.9, 6.0, 6.3 and 6.8. Interconversion of the 4.9 form to that isoelectric at pH 6.0 was noted during vacuum dialysis. Samples from normal human brain and from cases of Tay-Sachs disease were also examined and the results compared.     

Protein-protein interaction conferring stability to an extracellular acetyl (xylan) esterase produced by Termitomyces clypeatus

Acetyl esterase (AE) activity present in the culture filtrate of Termitomyces clypeatus was separated into lower molar mass (LMM) and higher molar mass (HMM) protein fractions during BioGel P-200 gel chromatography. AE was purified as a 30 kDa nonglycosylated protein from LMM fractions by CM-Sepharose ion exchange chromatography and HPGPLC. Although the HMM fraction had a number of enzyme activities (sucrase, beta-xylosidase, beta-glucosidase, and alpha-L-arabinofuranosidase) other than AE, protein present in the fraction was eluted as a single protein peak in HPGPLC and gave a single band in native PAGE. The fraction, subsequently purified by DEAE-Sephadex chromatography, was a SDS-PAGE homogeneous 80 kDa glycoprotein, but with both AE and cellobiase activities. The aggregate dissociated during ConA-Sepharose chromatography and 30 kDa AE and 56 kDa glycosylated cellobiase were purified separately. The dissociation caused significant loss of cellobiase activity but not that of AE. AE purified from both HMM and LMM fractions was characterized to be the same enzyme in terms of molar masses, pI (7.3), and other physicochemical properties. AE as an aggregate with cellobiase showed higher thermostability, temperature optimum, and resistance toward chemical denaturants than those of purified AE. Compared to cellobiase purified earlier from the same fungus, the enzyme present with AE in the aggregate also showed higher catalytic activity, thermostability, and temperature optimum. The study indicated that the formation of such SDS-resistant enzyme aggregate was associated with significant changes in the physicochemical properties of the enzymes, mainly toward improvement of rigidity of enzymes, and sometimes with the improvement of catalytic activity.     

The separation and characterization of marmoset kidney beta-D-galactosidase and beta-D-glucosidase.

beta-D-Galactosidase and beta-D-glucosidase activities were determined in homogenates of marmoset kidney by using the appropriate 4-methylumbelliferyl glycoside, beta-D-Galactosidase activity was separated into two main components by ion-exchange chromatography on DEAE-cellulose, starch-gel electrophoresis, isoelectric focusing and gel filtration on Sephadex G-200. One form designated A had a pI of 5.1, was loosely bound to DEAE-cellulose at pH7.0, remained near the origin on starch-gel electrophoresis at pH 7.0 and had an apparent molecular weight of 160000. The second beta-D-galactosidase component, designated B, was associated with the total beta-D-glucosidase activity, had a pI of 4.3, was firmly bound to DEAE-cellulose, migrated rapidly towards the anode on starch-gel electrophoresis and had an apparent molecular weight of 50000. The optimum pH values of beta-D-galactosidase A and B were 4.5 and 6.0 respectively. beta-D-Galactosidase A was activated by 0.1 M-NaC1 but the activity of the B form was inhibited by 1 M-NaC1 at pH 4.5. beta-D-galactosidase had a bimodal distribution, the A form being recovered in the lysosomal fraction whereas the B form was present in the soluble fraction, as was the major portion of the beta-D-glucosidase activity. The lysosomal and soluble forms were further characterized by DEAE-cellulose chromatography.     

Hydrolytic enzymes of Psoroptes cuniculi (Delafond)

Phosphatases, C4 and C8 esterases, leucine and valine aminopeptidases, N-acetyl-beta-glucosaminidase, beta-glucosidase, beta-galactosidase and beta-glucuronidase were detected in extracts of the parasitic mite Psoroptes cuniculi. Lipase, trypsin-like and chymotrypsin-like activities were not present. Haemoglobin was hydrolysed by a detergent-soluble fraction of the mite extracts with a maximum hydrolysis between pH 3 and 5. Acid proteinase activity was greater against haemoglobin than bovine serum albumin. Inhibitors of cysteine, serine and metallo-proteinases failed to inhibit the hydrolysis of H-Pro-Thr-Glu-Phe-Phe(NO2)-Arg-Leu-OH while pepstatin A inhibited its hydrolysis in a dose-dependent manner (IC50 8.02 x 10(-11) M (+/- 0.30 x 10(-11). Thermal inactivation of the proteolytic activity followed an exponential decay pattern. Typical K(m) and Vmax values were 7.2 x 10(-5) (+/- 0.7 x 10(-5) M-1 and 1.13 x 10(-3) (+/- 0.05 x 10(-3) OD unit-1 min-1 respectively. Acid proteinase activity eluted from a size exclusion column in a single, major peak representing a molecular weight range of 21-24.5 kDa. The major endoproteinase of P. cuniculi therefore appears to be a cathepsin D-like aspartic proteinase.     

Fractionation of cellulase and beta-glucosidase in a Trichoderma reesei culture liquid by use of two-phase partitioning

An aqueous two-phase system based on the two polymers poly(ethylene glycol) and dextran has been used for the fractionation of cellulase enzymes present in culture liquid obtained by fermentation with Trichoderma reesei. The activities of beta-glucosidase and glucanases were separated to high degree by using the two-phase systems for a counter-current distribution process in nine transfer steps. While the glucanases had high affinity to the poly(ethylene glycol) rich top phase the beta-glucosidase was enriched in the dextran-containing bottom phase. Multiple counter-current distribution performed indicates the heterogeneity of beta-glucosidase activities assuming at least four isoenzyme forms. One step concentration of beta-glucosidase by using system with 46:1 phase volume ratio resulted in 16 times higher enzyme activity.     

水牛瘤胃宏基因组的一个新的b-葡萄糖苷酶基因umcel3G的克隆、表达及其表达产物的酶学特性

以木质纤维素为原料、应用同步糖化共发酵工艺发酵生产酒精时需要酸性中低温高活力纤维素酶包括b-葡萄糖苷酶。本工作分6次构建了水牛瘤胃未培养微生物宏基因组文库, 获得1.26×105个克隆, 文库含外源DNA的总长度 约为4.8×106 kb。从文库中筛选到118个表达b-葡萄糖苷酶活性的独立克隆。发现其中8个克隆表达的b-葡萄糖苷酶在pH5.0、37oC条件下活性较强。对其中一个克隆进行了亚克隆, 序列分析发现一个2223 bp的潜在的编码b-葡萄糖苷酶基因(umcel3G)的开放阅读框(ORF), 其编码产物的氨基酸序列与来自于 Bacillus sp.的一个b-葡萄糖苷酶同源性最高, 具有60%的一致性和73%的相似性。该ORF在E.coli中的表达产物Umcel3G的分子量与预测大小相似, 酶谱分析表明该表达产物具有b-葡萄糖苷酶活性, 证实该基因为一个b-葡萄糖苷酶基因。测定了用Ni-NTA纯化的Umcel3G的酶学特性, 其最适pH和最适温度分别为6.0~6.5和45oC。一些金属离子如Ca2+、Zn2+能显著提高该酶的酶活, 而另外一些金属离子如Fe3+、Cu2+能抑制Umcel3G的活性。在pH4.5、35oC和5 mmol/L的 Ca2+存在的条件下, 用Ni-NTA纯化的重组酶的比活为22.8 IU/mg, 说明该酶在用SSCF工艺发酵生产酒精中有潜在的应用价值。     

Comparison of extracellular enzyme activities and community composition of attached and free-living bacteria in porous medium columns

Free-living and surface-associated microbial communities in sand-packed columns perfused with groundwater were compared by examination of compositional and functional characteristics. The composition of the microbial communities was assessed by bulk DNA extraction, PCR amplification of 16S ribosomal DNA fragments, separation of these fragments by denaturing gradient gel electrophoresis, and sequence analysis. Community function was assessed by measurement of beta-glucosidase and aminopeptidase extracellular enzyme activities. Free-living populations in the aqueous phase exhibited a greater diversity of phylotypes than populations associated with the solid phase. The attached bacterial community displayed significantly greater beta-glucosidase and aminopeptidase enzyme activities per volume of porous medium than those of the free-living community. On a per-cell basis, the attached community had a significantly higher cell-specific aminopeptidase enzyme activity (1.07 x 10(-7) nmol cell(-1) h(-1)) than the free-living community (5.02 x 10(-8) nmol cell(-1) h(-1)). Conversely, the free-living community had a significantly higher cell-specific beta-glucosidase activity (1.92 x 10(-6) nmol cell(-1) h(-1)) than the surface-associated community (6.08 x 10(-7) nmol cell(-1) h(-1)). The compositional and functional differences observed between these two communities may reflect different roles for these distinct but interacting communities in the decomposition of natural organic matter or biodegradation of xenobiotics in aquifers.     

Identification of two distinct antibacterial domains within the sequence of bovine alpha(s2)-casein.

Two distinct domains with antibacterial activity were isolated from a peptic hydrolysate of bovine alpha(s2)-casein. The digested alpha(s2)-casein was fractionated by cation-exchange chromatography, after which the peptides in the two active fractions obtained were separated by high-performance liquid chromatography and sequenced by electrospray-ionization tandem mass spectrometry. The major component in each active fraction, f(183-207) and f(164-179), was further purified and the antibacterial activity of these components was tested against several microorganisms. Depending on the target bacterial strain, these peptides exhibited minimum inhibitory concentrations between 8 and 99 microM. Peptide f(183-207) exhibited a consistently higher antibacterial activity than f(164-179), although both peptides showed a comparable hemolytic effect. A method of in situ enzymatic hydrolysis on a cation-exchange membrane to obtain a fraction enriched in the most active antibacterial domain is presented. The antibacterial and hemolytic activities are discussed in relation to the structure and hydrophobicity of the peptides.     

Isolation and properties of an extracellular beta-glucosidase from the polycentric rumen fungus Orpinomyces sp. strain PC-2.

An extracellular beta-glucosidase (EC 3.2.1.21) was purified from culture filtrate of the anaerobic rumen fungus Orpinomyces sp. strain PC-2 grown on 0.3% (wt vol-1) Avicel by using Q Sepharose anion-exchange chromatography, ammonium sulfate precipitation, chromatofocusing ion-exchange chromatography, and Superose 12 gel filtration. The enzyme is monomeric with a M(r) of 85,400, as estimated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, has a pI of 3.95, and contains about 8.5% (wt vol-1) carbohydrate. The N terminus appears to be blocked. The enzyme catalyzes the hydrolysis of cellobiose and p-nitrophenyl-beta-D-glucoside (PNPG). The Km and Vmax values with cellobiose as the substrate at pH 6.0 and 40 degrees C are 0.25 mM and 27.1 mumol.min-1 x mg-1, respectively; with PNPG as the substrate, the corresponding values are of 0.35 mM and 27.7 mumol.min-1 x mg-1. Glucose (Ki = 8.75 mM, with PNPG as the substrate) and gluconolactone (Ki = 1.68 x 10(-2) and 2.57 mM, with PNPG and cellobiose as the substrates, respectively) are competitive inhibitors. Optimal activity with PNPG and cellobiose as the substrates is at pH 6.2 and 50 degrees C. The enzyme has high activity against sophorose (beta-1,2-glucobiose) and laminaribiose (beta-1,3-glucobiose) but has no activity against gentiobiose (beta-1,6-glucobiose). The activity of the beta-glucosidase is stimulated by Mg2+, Mn2+, Co2+, and Ni2+ and inhibited by Ag+, Fe2+, Cu2+, Hg2+, SDS, and p-chloromercuribenzoate.