scholarly journals Cellulose hydrolysis by the cellulases from Trichoderma reesei: adsorptions of two cellobiohydrolases, two endocellulases and their core proteins on filter paper and their relation to hydrolysis

1994 ◽  
Vol 303 (3) ◽  
pp. 817-823 ◽  
Author(s):  
B Nidetzky ◽  
W Steiner ◽  
M Claeyssens
Keyword(s):  
Mass Transfer ◽  
Trichoderma Reesei ◽  
Filter Paper ◽  
Cellulose Hydrolysis ◽  
Solid Substrate ◽  
Bulk Liquid ◽  
Cellobiohydrolase I ◽  
Irreversible Adsorption ◽  
Core Proteins ◽  
Cellulose Binding

Separate binding of several purified cellulolytic components of Trichoderma reesei on to filter paper was studied and concomitant hydrolysis rates evaluated. Enhancement of mass transfer from the bulk liquid to the solid substrate by agitation has two different effects on adsorption depending on the type of enzyme: (i) the fraction of cellobiohydrolase II (CBH II) and endoglucanase III (EG III) bound at equilibrium is increased, whereas (ii) the rate but not the extent of cellobiohydrolase I (CBH I) and endoglucanase I (EG I) adsorption is affected. The adsorption of CBH I core, a component lacking the cellulose-binding domain (CBD), is, however, not significantly influenced by mass transfer. The CBH I interdomain peptide (present in CBH I core b) does not participate in adsorption but enhances stability. The adsorption of CBH I core proteins is a fully reversible process whereas that of the intact CBH I is not. Thus, the interaction of the CBD with filter paper apparently accounts for the mass-transfer-limited binding rate and also for the irreversible adsorption of intact CBH I. Adsorption isotherms at 50 degrees C indicate very similar relative association constants for the intact cellulases (0.24-0.30 l/g of cellulose), but drastically reduced values for CBH I core proteins (0.03 l/g of cellulose). The specific activities of adsorbed CBH I and of its core proteins are identical and a linear relationship between adsorption and rates of hydrolysis is found only for these enzymes. Thus, non-productive binding on to cellulose seems evident in the case of CBH II and EG III but not CBH I.

scholarly journals Cellulose hydrolysis by the cellulases from Trichoderma reesei: a new model for synergistic interaction

1994 ◽  
Vol 298 (3) ◽  
pp. 705-710 ◽  
Author(s):  
B Nidetzky ◽  
W Steiner ◽  
M Hayn ◽  
M Claeyssens
Keyword(s):  
Trichoderma Reesei ◽  
Filter Paper ◽  
Cellulose Hydrolysis ◽  
Catalytic Core ◽  
Core Proteins ◽  
Hydrolysis Rates ◽  
Cellulose Binding ◽  
The Mathematical Model ◽  
Hydrolysis Of ◽  
Synergistic Combinations

The hydrolysis of Whatman no. 1 filter paper by purified cellulolytic components from Trichoderma reesei and the synergistic action of binary combinations of these enzymes on the same substrate were investigated. At 20 milligrams filter paper, enzyme concentrations needed to obtain half-maximal hydrolysis rates (KE values) were in the 3-4 microM range for the cellobiohydrolases (CBHs) and 0.05-0.10 microM for the endoglucanases (EGs). Catalytic-core proteins of CBH I and EG III, lacking the cellulose-binding domain, exhibit KE values 2.3 and 5.1 times higher than those of the intact enzymes. In synergistic combinations of two cellulases, the KE value of at least one enzyme was 3-10-fold reduced. CBH I/CBH II and CBH I/EG III combinations showed the most powerful synergism, and optimal ratios were a function of the total protein concentration. Results obtained in activity and adsorption assays using filter paper pretreated with one component, followed by inactivation and subsequent hydrolysis with the same or another cellulase component, point to a sequential enzymic attack of the cellulose and seems consistent with the mathematical model presented.

Crystallization and Preliminary X-ray Studies on the Core Proteins of Cellobiohydrolase I and Endoglucanase I from Trichoderma reesei

1993 ◽  
Vol 234 (3) ◽  
pp. 905-907 ◽  
Author(s):  
Christina Divne ◽  
Irmgard Sinning ◽  
Jerry Ståhlberg ◽  
Göran Pettersson ◽  
Michael Bailey ◽  
...  
Keyword(s):  
Trichoderma Reesei ◽  
Cellobiohydrolase I ◽  
X Ray ◽  
The Core ◽  
Core Proteins ◽  
Endoglucanase I

Adsorption and Activity of Trichoderma reesei Cellobiohydrolase I, Endoglucanase II, and the Corresponding Core Proteins on Steam Pretreated Willow

1999 ◽  
Vol 81 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Pia Kotiranta ◽  
Johan Karlsson ◽  
Matti Siika-Aho ◽  
József Medve ◽  
Liisa Viikari ◽  
...  
Keyword(s):  
Trichoderma Reesei ◽  
Cellobiohydrolase I ◽  
Endoglucanase Ii ◽  
Core Proteins

scholarly journals Roles of the Catalytic Domain and Two Cellulose Binding Domains of Thermomonospora fusca E4 in Cellulose Hydrolysis

1998 ◽  
Vol 180 (7) ◽  
pp. 1709-1714 ◽  
Author(s):  
Diana Irwin ◽  
Dong-Hoon Shin ◽  
Sheng Zhang ◽  
Brian K. Barr ◽  
Joshua Sakon ◽  
...  
Keyword(s):  
Filter Paper ◽  
Recombinant Dna ◽  
Catalytic Domain ◽  
Cellulose Hydrolysis ◽  
Hydrolytic Activity ◽  
Thermomonospora Fusca ◽  
Binding Domains ◽  
The Family ◽  
Recombinant Dna Techniques ◽  
Cellulose Binding

ABSTRACT Thermomonospora fusca E4 is an unusual 90.4-kDa endocellulase comprised of a catalytic domain (CD), an internal family IIIc cellulose binding domain (CBD), a fibronectinlike domain, and a family II CBD. Constructs containing the CD alone (E4-51), the CD plus the family IIIc CBD (E4-68), and the CD plus the fibronectinlike domain plus the family II CBD (E4-74) were made by using recombinant DNA techniques. The activities of each purified protein on bacterial microcrystalline cellulose (BMCC), filter paper, swollen cellulose, and carboxymethyl cellulose were measured. Only the whole enzyme, E4-90, could reach the target digestion of 4.5% on filter paper. Removal of the internal family IIIc CBD (E4-51 and E4-74) decreased activity markedly on every substrate. E4-74 did bind to BMCC but had almost no hydrolytic activity, while E4-68 retained 32% of the activity on BMCC even though it did not bind. A low-activity mutant of one of the catalytic bases, E4-68 (Asp55Cys), did bind to BMCC, although E4-51 (Asp55Cys) did not. The ratios of soluble to insoluble reducing sugar produced after filter paper hydrolysis by E4-90, E4-68, E4-74, and E4-51 were 6.9, 3.5, 1.3, and 0.6, respectively, indicating that the family IIIc CBD is important for E4 processivity.

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