Substrate Specificities of GH8, GH39, and GH52 β-xylosidases from Bacillus halodurans C-125 Toward Substituted Xylooligosaccharides

The glutathione S-transferases that were purified to homogeneity from liver cytosol have overlapping but distinct substrate specificities and different isoelectric points. This report explores the possibility of using preparative electrofocusing to compare the composition of the transferases in liver and kidney cytosol. Hepatic cytosol from adult male Sprague–Dawley rats was resolved by isoelectric focusing on Sephadex columns into five peaks of transferase activity, each with characteristic substrate specificity. The first four peaks of transferase activity (in order of decreasing basicity) are identified as transferases AA, B, A and C respectively, on the basis of substrate specificity, but the fifth peak (pI6.6) does not correspond to a previously described transferase. Isoelectric focusing of renal cytosol resolves only three major peaks of transferase activity, each with narrow substrate specificity. In the kidney, peak 1 (pI9.0) has most of the activity toward 1-chloro-2,4-dinitrobenzene, peak 2 (pI8.5) toward p-nitrobenzyl chloride, and peak 3 (pI7.0) toward trans-4-phenylbut-3-en-2-one. Renal transferase peak 1 (pI9.0) appears to correspond to transferase B on the basis of pI, substrate specificity and antigenicity. Kidney transferase peaks 2 (pI8.5) and 3 (pI7.0) do not correspond to previously described glutathione S-transferases, although kidney transferase peak 3 is similar to the transferase peak 5 from focused hepatic cytosol. Transferases A and C were not found in kidney cytosol, and transferase AA was detected in only one out of six replicates. Thus it is important to recognize the contribution of individual transferases to total transferase activity in that each transferase may be regulated independently.

Download Full-text

A globin-coupled oxygen sensor from the facultatively alkaliphilic Bacillus halodurans C-125

Extremophiles ◽

10.1007/s007920100220 ◽

2001 ◽

Vol 5 (5) ◽

pp. 351-354 ◽

Cited By ~ 16

Author(s):

Shaobin Hou ◽

Claude Belisle ◽

Summer Lam ◽

Mikhail Piatibratov ◽

Victor Sivozhelezov ◽

...

Keyword(s):

Oxygen Sensor ◽

Bacillus Halodurans ◽

Alkaliphilic Bacillus

Download Full-text

Substrate specificities of active transport systems for amino acids in vacuolar-membrane vesicles of Saccharomyces cerevisiae. Evidence of seven independent proton/amino acid antiport systems.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)90890-2 ◽

1984 ◽

Vol 259 (18) ◽

pp. 11505-11508 ◽

Cited By ~ 5

Author(s):

T Sato ◽

Y Ohsumi ◽

Y Anraku

Keyword(s):

Saccharomyces Cerevisiae ◽

Amino Acids ◽

Amino Acid ◽

Active Transport ◽

Membrane Vesicles ◽

Vacuolar Membrane ◽

Transport Systems ◽

Substrate Specificities

Download Full-text

Kinetic properties and substrate specificities of two cellulases from auxin-treated pea epicotyls.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)40670-3 ◽

1977 ◽

Vol 252 (4) ◽

pp. 1402-1407

Author(s):

Y S Wong ◽

G B Fincher ◽

G A Maclachlan

Keyword(s):

Kinetic Properties ◽

Substrate Specificities

Download Full-text

Extraction of sugarcane bagasse arabinoxylan, integrated with enzymatic production of xylo-oligosaccharides and separation of cellulose

Biotechnology for Biofuels ◽

10.1186/s13068-021-01993-z ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Leila Khaleghipour ◽

Javier A. Linares-Pastén ◽

Hamid Rashedi ◽

Seyed Omid Ranaei Siadat ◽

Andrius Jasilionis ◽

...

Keyword(s):

Sugarcane Bagasse ◽

Sugar Content ◽

Value Added ◽

Apparent Molecular Weight ◽

Bacillus Halodurans ◽

Glycoside Hydrolase Family ◽

High Concentration ◽

Enzymatic Production ◽

Successful Separation ◽

Ft Ir

AbstractSugarcane processing roughly generates 54 million tonnes sugarcane bagasse (SCB)/year, making SCB an important material for upgrading to value-added molecules. In this study, an integrated scheme was developed for separating xylan, lignin and cellulose, followed by production of xylo-oligosaccharides (XOS) from SCB. Xylan extraction conditions were screened in: (1) single extractions in NaOH (0.25, 0.5, or 1 M), 121 °C (1 bar), 30 and 60 min; (2) 3 × repeated extraction cycles in NaOH (1 or 2 M), 121 °C (1 bar), 30 and 60 min or (3) pressurized liquid extractions (PLE), 100 bar, at low alkalinity (0–0.1 M NaOH) in the time and temperature range 10–30 min and 50–150 °C. Higher concentration of alkali (2 M NaOH) increased the xylan yield and resulted in higher apparent molecular weight of the xylan polymer (212 kDa using 1 and 2 M NaOH, vs 47 kDa using 0.5 M NaOH), but decreased the substituent sugar content. Repeated extraction at 2 M NaOH, 121 °C, 60 min solubilized both xylan (85.6% of the SCB xylan), and lignin (84.1% of the lignin), and left cellulose of high purity (95.8%) in the residuals. Solubilized xylan was separated from lignin by precipitation, and a polymer with β-1,4-linked xylose backbone substituted by arabinose and glucuronic acids was confirmed by FT-IR and monosaccharide analysis. XOS yield in subsequent hydrolysis by endo-xylanases (from glycoside hydrolase family 10 or 11) was dependent on extraction conditions, and was highest using xylan extracted by 0.5 M NaOH, (42.3%, using Xyn10A from Bacillus halodurans), with xylobiose and xylotriose as main products. The present study shows successful separation of SCB xylan, lignin, and cellulose. High concentration of alkali, resulted in xylan with lower degree of substitution (especially reduced arabinosylation), while high pressure (using PLE), released more lignin than xylan. Enzymatic hydrolysis was more efficient using xylan extracted at lower alkaline strength and less efficient using xylan obtained by PLE and 2 M NaOH, which may be a consequence of polymer aggregation, via remaining lignin interactions.

Download Full-text