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1.
α-Agarase hydrolyzes the α-1,3 linkage of agarose yielding agaro-oligosaccharides. It is less well characterized than β-agarase.
AgaA gene (2.3 kb ORF), encoding the α-agarase from Thalassomonas JAMB A33, was subcloned into both a constitutive and an inducible expression vector. Both the constructed plasmids, pVT-AgaA
(ADH1 promoter) and pYInu-AgaA (GAL10 promoter), were transformed into Saccharomyces cerevisiae SEY2102 and FY833 and pPIC9-AgaA harboring the AOX1 promoter was transformed into Pichia pastoris GS115. The recombinant α-agarases were over-expressed with activities from 0.3 to 1.6 unit/ml, the highest being in the SEY2102/pYInu-AgaA
transformant. Most of the recombinant α-agarase was extracellular because each plasmid possesses a signal sequence for the
secretory production of α-agarase. In contrast, the Pichia host-vector expression system was unsuitable for the production of recombinant α-agarase. This is the first report of recombinant
production of α-agarase in yeast for industrial use. 相似文献
2.
Chemical structure and quality of agars from Gracilaria 总被引:3,自引:0,他引:3
Erminio Murano 《Journal of applied phycology》1995,7(3):245-254
Agar polymers synthesized by species of the genus Gracilaria constitute a complex mixture of molecules, containing several extremes in structure. Sulphate hemi-esters, methyl ethers
and pyruvic ketals can alter in a number of ways the structural regularity of agar based on strictly 3-O-linked β-l-galactopyranose and 4-O-linked α-l-galactopyranose residues. In comparison with agars from Gelidium and Pterocladia, agars from Gracilaria can have higher degrees of sulphation, methoxylation and pyruvylation. The gelling ability of agars from most of Gracilaria species is considerably improved by adopting, before extraction, an alkali pretreatment which converts α-l-galactose 6 sulphate into 3,6-anhydro-α-l-galactose. Native agars obtained from Gracilaria cannot be classified, with few exceptions, as bacteriological grade agar as they have a high content of methoxyls and consequently
high gelling temperatures. On the contrary, the genus Gracilaria is considered the most important source of food and sugar-reactive grade agars.
Among techniques which can be used to study algal polysaccharides, combined 1H and 13C nuclear magnetic resonance spectroscopy represent the most effective and powerful method for the investigation of the chemical
structure of agarocolloids. 相似文献
3.
J. Q. Liu S. Ito T. Dairi N. Itoh S. Shimizu H. Yamada 《Applied microbiology and biotechnology》1998,49(6):702-708
Low-specificity l-threonine aldolase, catalyzing the reversible cleavage/condensation reaction between l-threonine/l-allo-threonine and glycine plus acetaldehyde, was purified to homogeneity from Pseudomonas sp. NCIMB 10558. The enzyme has an apparent molecular mass of approximately 145 kDa and consists of four identical subunits
with a molecular mass of 38 kDa. The enzyme, requiring pyridoxal- 5′-phosphate as a coenzyme, is strictly l-specific at the α position, whereas it can not distinguish between threo and erythro forms at the β position. Besides the reversible cleavage/condensation of threonine, the enzyme also catalyzes the reversible
interconversion between glycine plus various aldehydes and l-β-hydroxy-α-amino acids, including l-β-(3,4-dihydroxyphenyl)serine, l-β-(3,4-met‐hylenedioxyphenyl)serine and l-β-phenylserine, providing a new route for the industrial production of these important amino acids.
Received: 10 November 1997 / Received revision: 7 January 1998 / Accepted 30 January 1998 相似文献
4.
Birichevskaya LL Kvach SV Sivets GG Kalinichenko EN Zinchenko AI Mikhailopulo IA 《Biotechnology letters》2007,29(4):585-591
Enzymatic 5′-monophosphorylation and 5′-phosphatidylation of a number of β-l- and β-d-nucleosides was investigated. The first reaction, catalyzed by nucleoside phosphotransferase (NPT) from Erwinia herbicola, consisted of the transfer of the phosphate residue from p-nitrophenylphosphate (p-NPP) to the 5′-hydroxyl group of nucleoside; the second was the phospholipase d (PLD)-catalyzed transphosphatidylation of l-α-lecithin with a series of β-l- and β-d-nucleosides as the phosphatidyl acceptor resulted in the formation of the respective phospholipid-nucleoside conjugates.
Some β-l-nucleosides displayed similar or even higher substrate activity compared to the β-d-enantiomers. 相似文献
5.
Lactococcus lactis subspecies cremoris SBT 0495 produces the phosphopolysaccharide viilian, which consists of the repeating unit β-d-glucosyl-(1→4)-(α-l-rhamnosyl-(1→2))-(α-d-galactose-1-phosphoryl-(→3)-β-galactosyl-(1→4)-β-d-glucose. A lipid extract was prepared from cells in the late exponential phase of growth and was hydrolyzed by hydrochloric
acid under mild conditions to split lipid-linked intermediates in the extract into lipid and sugar moieties. Both moieties
were purified by chromatographic techniques and were characterized to identify intermediates of the viilian biosynthetic pathway.
A polyisoprenoid isolated from the chloroform-soluble fraction of the hydrolyzed lipid extract was identified by mass spectrometry
as undecaprenol. Saccharides isolated from the water-soluble fraction of the hydrolyzed lipid extract by anion-exchange chromatography,
were characterized by glycosidic linkage analysis to discriminate sugar moieties of intermediates of viilian biosynthesis
from compounds liberated from cell wall components. Some oligosaccharide analogues contain a glycerol residue, suggesting
that these are fragments of glycosylglycerides and/or lipoteichoic acid. Three fragments were identified to be glucose, galactosyl-(1→4)-glucose,
and rhamnosyl-(1→2)-galactosyl-(1→4)-glucose, which are in agreement with the structure of the repeating unit of viilian.
These saccharides most likely represent the first three steps of the sequential assembly of the repeating unit of the undecaprenol
assembly.
Received: 2 November 1998 / Accepted: 3 March 1999 相似文献
6.
Nina Dückers Katrin Baer Sabine Simon Harald Gröger Werner Hummel 《Applied microbiology and biotechnology》2010,88(2):409-424
Threonine aldolases (TAs) constitute a powerful tool for catalyzing carbon–carbon bond formations in synthetic organic chemistry,
thus enabling an enantio- and diastereoselective synthesis of β-hydroxy-α-amino acids. Starting from the achiral precursors
glycine and an aldehyde, two new stereogenic centres are formed in this catalytic step. The resulting chiral β-hydroxy-α-amino
acid products are important precursors for pharmaceuticals such as thiamphenicol, a l-threo-phenylserine derivative or l-threo-3,4-dihydroxyphenylserine. TAs are pyridoxal-5-phosphate-dependent enzymes, which, in nature, catalyze the cleavage of l-threonine or l-allo-threonine to glycine and acetaldehyde in a glycine biosynthetic pathway. TAs from a broad number of species of bacteria and
fungi have been isolated and characterised as biocatalysts for the synthesis of β-hydroxy-α-amino acids. In this review, screening
methods to obtain novel TAs, their biological function, biochemical characterisation and preparative biotransformations with
TAs are described. 相似文献
7.
A novel phosphorylase from Clostridium phytofermentans belonging to the glycoside hydrolase family (GH) 65 (Cphy1874) was characterized. The recombinant Cphy1874 protein produced
in Escherichia coli showed phosphorolytic activity on nigerose in the presence of inorganic phosphate, resulting in the release of d-glucose and β-d-glucose 1-phosphate (β-G1P) with the inversion of the anomeric configuration. Kinetic parameters of the phosphorolytic activity
on nigerose were k
cat = 67 s−1 and K
m = 1.7 mM. This enzyme did not phosphorolyze substrates for the typical GH65 enzymes such as trehalose, maltose, and trehalose
6-phosphate except for a weak phosphorolytic activity on kojibiose. It showed the highest reverse phosphorolytic activity
in the reverse reaction using d-glucose as the acceptor and β-G1P as the donor, and the product was mostly nigerose at the early stage of the reaction. The
enzyme also showed reverse phosphorolytic activity, in a decreasing order, on d-xylose, 1,5-anhydro-d-glucitol, d-galactose, and methyl-α-d-glucoside. All major products were α-1,3-glucosyl disaccharides, although the reaction with d-xylose and methyl-α-d-glucoside produced significant amounts of α-1,2-glucosides as by-products. We propose 3-α-d-glucosyl-d-glucose:phosphate β-d-glucosyltransferase as the systematic name and nigerose phosphorylase as the short name for this Cphy1874 protein. 相似文献
8.
An DS Cui CH Sung BH Yang HC Kim SC Lee ST Im WT Kim SG 《Applied microbiology and biotechnology》2012,94(3):673-682
The gene encoding an α-l-arabinofuranosidase that could biotransform ginsenoside Rc {3-O-[β-d-glucopyranosyl-(1–2)-β-d-glucopyranosyl]-20-O-[α-l-arabinofuranosyl-(1–6)-β-d-glucopyranosyl]-20(S)-protopanaxadiol} to ginsenoside Rd {3-O-[β-d-glucopyranosyl-(1–2)-β-d-glucopyranosyl]-20-O-β-d-glucopyranosyl-20(S)-protopanaxadiol} was cloned from a soil bacterium, Rhodanobacter ginsenosidimutans strain Gsoil 3054T, and the recombinant enzyme was characterized. The enzyme (AbfA) hydrolyzed the arabinofuranosyl moiety from ginsenoside
Rc and was classified as a family 51 glycoside hydrolase based on amino acid sequence analysis. Recombinant AbfA expressed
in Escherichia coli hydrolyzed non-reducing arabinofuranoside moieties with apparent K
m values of 0.53 ± 0.07 and 0.30 ± 0.07 mM and V
max values of 27.1 ± 1.7 and 49.6 ± 4.1 μmol min−1 mg−1 of protein for p-nitrophenyl-α-l-arabinofuranoside and ginsenoside Rc, respectively. The enzyme exhibited preferential substrate specificity of the exo-type
mode of action towards polyarabinosides or oligoarabinosides. AbfA demonstrated substrate-specific activity for the bioconversion
of ginsenosides, as it hydrolyzed only arabinofuranoside moieties from ginsenoside Rc and its derivatives, and not other sugar
groups. These results are the first report of a glycoside hydrolase family 51 α-l-arabinofuranosidase that can transform ginsenoside Rc to Rd. 相似文献
9.
Proteins have been considered to consist exclusively of l-amino acids in living tissues. However, our previous studies showed that two specific aspartyl (Asp) residues in αA- and
αB-crystallins from human eye lenses invert to the d-isomers to a high degree during aging. The reaction is also accompanied by isomerization into a form containing β-Asp (isoaspartate)
residues. The appearance of d- and β-Asp in a protein potentially induces large changes to the higher order structure of the protein as well as to its
function. However, it remains unclear whether the formation of the Asp isomer is the direct trigger of the change to the higher
order structure and function. In this study, in order to clarify the effect of the inversion to d-isomers in a protein, we synthesized peptides corresponding to the 70–88 (KFVIFLDVKHFSPEDLTVK) fragment of human αA-crystallin
and its corresponding diastereoisomers in which lα-Asp was replaced with lβ-Asp, dα-Asp, and dβ-Asp at position 76 and compared their biochemical properties with that of normal peptide. The peptides containing abnormal
isomers (lβ-Asp, dα-Asp, and dβ-Asp residues, respectively) were more hydrophilic than the normal peptide (containing lα-Asp), lost β-sheet structure and changed to random structures. The normal peptide promoted the aggregation of insulin while
the other three isomers suppressed the aggregation of insulin. This is the first evidence that a single substitution of an
Asp isomer in a peptide induces a large change to the properties of the peptide. 相似文献
10.
Effects of a few amino acid analogs on growth and heterocyst differentiation have been studied in two nitrogen-fixing species
ofAnabaena. All the analogs except α-methyl-dl-aspartic acid inhibited growth. Exposure ofAnabaena doliolum, todl-5-fluorotryptophan anddl-p-fluorophenylalanine caused pronounced fragmentation of filaments into single cells. At low concentrations (0.01 mM), α-methyl-dl-aspartic acid stimulated growth of the strain ofA. doliolum as well as the strain of the second (unidentified)Anabaena species. Ethionine,dl-p-fluorophenylalanine,dl-5-fluorotryptophan, and canavanine blocked heterocyst differentiation, whereas α-methyl-dl-aspartic acid, α-methyl-dl-methionine,N-o-nitrophenylsulfenyl-l-tryptophan, norleucine, andS-2-aminoethyl-l-cysteine did not show any significant effect. Treatment with 7-azatryptophan,dl-β-hydroxynorvaline,l-methionine-dl-sulfoximine,l-methionine sulfone, and β-2-thienyl-dl-alanine led to a twofold increase in heterocyst frequency. Possible modes of action of the analogs in growth inhibition and
changes in heterocyst frequency are discussed. 相似文献
11.
Fuchs Viola Jaeger Karl-Erich Wilhelm Susanne Rosenau Frank 《World journal of microbiology & biotechnology》2011,27(3):713-718
A gene encoding a so far uncharacterized β-peptidyl aminopeptidase from the opportunistic human pathogen Pseudomonas aeruginosa PAO1 was cloned and actively expressed in the heterologue host Escherichia coli. The gene was identified in the genome sequence by its homology to the S58 family of peptidases. The sequence revealed an
open reading frame of 1,101 bp with a deduced amino acid sequence of 366 amino acids. The gene was amplified by PCR, ligated
into pET22b(+) and was successfully expressed in E. coli BL21 (DE3). It was shown that the enzyme consists of two polypeptides (α- and β-subunit), which are processed from the precursor.
The enzyme is specific for N-terminal β-alanyl dipeptides (β-Ala-Xaa). BapF hydrolyses efficiently β-alanine at the N-terminal
position, including H-β3hAla-pNA, H–D-β3hAla-pNA and β-Ala-l-His (l-carnosine). d- and l-alaninamide were also hydrolysed by the enzyme. 相似文献
12.
The structure of furcellarans obtained from red algae Furcellaria lumbricalis collected in Estonia was determined. Native and alkali-modified furcellarans were examined by gas chromatography/mass spectrometry
(GC/MS), and 13C-nuclear magnetic resonance spectroscopy (NMR) and were compared with commercial furcellaran (FMC Food Ingredients). The
polysaccharide preparation consisted mainly of (1→3) linked β-D-galactopyranose, (1→4) linked 3,6-anhydro-α-D-galactopyranose and (1→3) linked β-D-galactopyranose 4-sulphate. Alkaline treatment removed the sulphate precursor sequences with formation of 3,6-anhydrogalactose
that improved the furcellaran gelling ability. 相似文献
13.
Sgambati E Marini M Vichi D Zappoli Thyrion GD Parretti E Mello G Gheri G 《Histochemistry and cell biology》2007,128(3):263-273
The aim of this study was to investigate the distribution of the oligosaccharides of the glycoconjugates in placentas from
pregnancies complicated by different degree of altered glycaemia. Placentas from women with physiological pregnancies (group
1), with pregnancies complicated by minor degree of glucose intolerance (group 2) and with pregnancies complicated by gestational
diabetes mellitus (GDM) treated with insulin (group 3) were collected. Ten lectins were used (ConA, WGA, PNA, SBA, DBA, LTA,
UEA I, GSL II, MAL II and SNA) in combination with chemical and enzymatic treatments. The data showed a decrease of sialic
acid linked α(2–6) to galactose/N-acetyl-d-galactosamine and an increase of N-acetyl-d-glucosamine in the placentas of the pathological groups, in particular the group 3, comparing to the group 1. A decrease
of l-fucose (LTA) and d-galactose-(β1–3)-N-acetyl-d-galactosamine, and an increase and/or appearance of l-fucose (UEA I) and N-acetyl-d-galactosamine were observed in both the pathological groups, particularly in the group 2, with respect to the group 1. In
GDM, and even in pregnancies with a simple alteration of maternal glycaemia, the changes in the distribution of oligosaccharides
could be related to alteration of the structure and functionality of the placenta. 相似文献
14.
Eniade A Purushotham M Ben RN Wang JB Horwath K 《Cell biochemistry and biophysics》2003,38(2):115-124
Structurally diverse carbon-linked (C-linked) analogs of antifreeze glycoprotein (AFGP) have been prepared via linear or convergent
solid phase synthesis. These analogs range in molecular weight from approx 1.5–4.1 KDa and do not possess the β-d-galactose-1,3-α-d-N-acetylgalactosamine carbohydrate moiety or the l-threonine-l-alanine-l-alanine polypeptide backbone native to the AFGP wild-type. Despite these dramatic structural modifications, the 2.7-KDa and
4.1-KDa analogs possess antifreeze protein-specific activity as determined by recrystallization-inhibition (RI) and thermal
hysteresis (TH) assays. These analogs are weaker than the wild-type in their activity, but nanoliter osmometry indicates that
these compounds are binding to ice and affecting a localized freezing point depression. This is the first example of a C-linked
AFGP analog that possesses TH and RI activity and suggests that the rational design and synthesis of chemically and biologically
stable AFGP analogs is a feasible and worthwhile endeavor. Given the low degree of TH activity, these compounds may prove
useful for the protection of cells during freezing and thawing cycles. 相似文献
15.
Gen-Hai Zhao Hui Li Wei Liu Wei-Guo Zhang Fei Zhang Qian Liu Qing-Cai Jiao 《Amino acids》2011,40(1):215-220
In this research, an improved method for preparation of optically pure β-hydroxy-α-amino acids, catalyzed by serine hydroxymethyl
transferase with threonine aldolase activity, is reported. Using recombinant serine hydroxymethyl transferase (SHMT), an enzymatic
resolution process was established. A series of new substrates, β-phenylserine, β-(nitrophenyl) serine and β-(methylsulfonylphenyl)
serine were used in the resolution process catalyzed by immobilized Escherichia coli cells with SHMT activity. It was observed that the K
m for l-threonine was 28-fold higher than that for l-allo-threonine, suggesting that this enzyme can be classified as a low-specificity l-allo-threonine aldolase. The results also shows that SHMT activity with β-phenylserine as substrate was about 1.48-fold and 1.25-fold
higher than that with β-(methylsulfonylphenyl) serine and β-(nitrophenyl) serine as substrate, respectively. Reaction conditions
were optimized by using 200 mmol/l β-hydroxy-α-amino acid, and 0.1 g/ml of immobilized SHMT cells at pH 7.5 and 45°C. Under
these conditions, the immobilized cells were continuously used 10 times, yielding an average conversion rate of 60.4%. Bead
activity did not change significantly the first five times they were used, and the average conversion rate during the first
five instances was 84.1%. The immobilized cells exhibited favourable operational stability. 相似文献
16.
Tomofumi Okuno Shin Ji Motobayashi Hitoshi Ueno Katsuhiko Nakamuro 《Biological trace element research》2005,106(1):77-93
The objective of this study was to purify and characterize a mouse hepatic enzyme that directly generates CH3SeH from seleno-l-methionine (l-SeMet) by the α,γ-elimination reaction. The l-SeMet α,γ-elimination enzyme was ubiquitous in tissues from ICR mice and the activity was relatively high in the large intestine,
brain, and muscle, as well as the liver. Aging and sex of the mice did not have any significant influence on the activity
in the liver. The enzyme was purified from the mouse liver by ammonium sulfate precipitation and four kinds of column chromatography.
These procedures yielded a homogeneous enzyme, which was purified approx 1000-fold relative to mouse liver extract. Overall
recovery was approx 8%. The purified enzyme had a molecular mass of approx 160 kDa with four identical subunits. The K
m
value of the enzyme for the catalysis of l-SeMet was 15.5 m M, and the V
max was 0.29 units/mg protein. Pyridoxal 5′-phosphate (pyridoxal-P) was required as a cofactor because the holoenzyme could be
resolved to the apoenzyme by incubation with hydroxylamine and reconstituted by addition of pyridoxal-P. The enzyme showed
the optimum activity at around pH 8.0 and the highest activity at 50°C; it catalyzed the α,γ-elimination reactions of several
analogs such as d,l-homocysteine and l-homoserine in addition to l-SeMet. This enzyme also catalyzed the α,β-elimination reaction of Se-methylseleno-l-cysteine. However, l-methionine was inerts. Therefore, the purified enzyme was different from the bacterial l-methionine γ-lyase that metabolizes l-SeMet to CH3SeH, in terms of the substrate specificity. These results were the first identification of a mammalian enzyme that specifically
catalyzes the α,γ-elimination reaction of l-SeMet and immediately converts it to CH3SeH, an important metabolite of Se. 相似文献
17.
Bionda N Cudic M Barisic L Stawikowski M Stawikowska R Binetti D Cudic P 《Amino acids》2012,42(1):285-293
Abstract
A simple and practical general synthetic protocol towards orthogonally protected tHyAsp derivatives fully compatible with Fmoc solid-phase peptide synthetic methodology is reported. Our approach includes enantioresolution of commercially available d,l-tHyAsp racemic mixture by co-crystallization with l-Lys, followed by ion exchange chromatography yielding enantiomerically pure l-tHyAsp and d-tHyAsp, and their selective orthogonal protection. In this way N α -Fmoc protected tHyAsp derivatives were prepared ready for couplings via either α- or β-carboxylic group onto the resins or the growing peptide chain. In addition, coupling of tHyAsp via β-carboxylic group onto amino resins allows preparation of peptides containing tHyAsn sequences, further increasing the synthetic utility of prepared tHyAsp derivatives. 相似文献18.
Knoll C du Toit M Schnell S Rauhut D Irmler S 《Applied microbiology and biotechnology》2011,89(4):1051-1060
Sulphur-containing compounds in wine have been extensively studied because of their effect on wine flavour and quality. In
this study, an enzyme that degrades sulphur-containing amino acids was cloned and characterised from two Oenococcus oeni strains of oenological origins. The enzyme has features of a cystathionine-γ-lyase (EC 4.4.1.1), a pyridoxal-5-phosphate-dependent
enzyme catalysing an α,γ-elimination reaction of l-cystathionine to produce l-cysteine, α-ketobutyrate and ammonia. Moreover, it was able to catalyse an α,β-elimination reaction producing homocysteine,
pyruvate and ammonia from l-cystathionine. An elimination reaction of l-cysteine and dl-homocysteine was also efficiently catalysed by the enzyme, resulting in the formation of hydrogen sulphide. Furthermore,
the ability to demethiolate methionine into methanethiol, an unfavourable volatile sulphur compound in terms of wine aroma,
was observed. The findings of this work suggest that O. oeni seems to play a minor role in the production of volatile sulphur compounds during the vinification process as the optimal
conditions were far from the harsh wine environment. 相似文献
19.
Camila Ramos dos Santos Fábio Márcio Squina Andréia Meza Navarro Daiane Patrícia Oldiges Adriana Franco Paes Leme Roberto Ruller Andrew John Mort Rolf Prade Mário Tyago Murakami 《Biotechnology letters》2011,33(1):131-137
A hyperthermostable glycoside hydrolase family 51 (GH51) α-l-arabinofuranosidase from Thermotoga petrophila RKU-1 (TpAraF) was cloned, overexpressed, purified and characterized. The recombinant enzyme had optimum activity at pH 6.0
and 70°C with linear α-1,5-linked arabinoheptaose as substrate. The substrate cleavage pattern monitored by capillary zone
electrophoresis showed that TpAraF is a classical exo-acting enzyme producing arabinose as its end-product. Far-UV circular
dichroism analysis displayed a typical spectrum of α/β barrel proteins analogously observed for other GH51 α-l-arabinofuranosidases. Moreover, TpAraF was crystallized in two crystalline forms, which can be used to determine its crystallographic
structure. 相似文献
20.
Joël Fleurence Laurence Massiani Odile Guyader Serge Mabeau 《Journal of applied phycology》1995,7(4):393-397
The effect of polysaccharidases (κ-carrageenase, β-agarase, xylanase, cellulase) on the protein extraction from three rhodophytes
has been studied. The kinetic parameters (apparent V
m, apparent K
m) and the optimum activity conditions (pH, temperature) of each enzyme were determined by using pure substrates. All the tested
enzymes possess Michaelis Menten mechanism with estimated substrate saturating concentrations of 8 000 mg l−1(carrageenan) for κ-carrageenase, 8 000 mg l−1 (agar) for β-agarase, 5000 mg l−1 (xylane) for β-xylanase and 6 000 mg l−1 (carboxymethylcellulose) for cellulase. The optimum activity conditions are pH 6.5–6.8 at 45°C for carrageenase, pH 6–6.5
at 55°C for agarase, pH 5 at 55°C for xylanase and pH 3.8 at 50°C for cellulose. Different alga/enzymes couples (κ-carrageenase/Chondrus crispus, β-agarase/Gracilaria verrucosa, β-xylanase/Palmaria palmata) were tested under the optimum activity conditions. Alga/cellulase + specific enzyme (e.g. Chondrus crispus/carrageenase + cellulase) systems were also studied at the optimum activity conditions of a specific enzyme (e.g. carageenase).
The use of the only cellulose was also tested on each alga. Except for Palmaria palmata, the highest protein yields were observed with the procedures using cellulase coupled with carrageenase or agarase for an
incubation period limited to 2 h. The Chondrus crispus/carrageenase + cellulose and Gracilaria verrucosa/agarase + cellulase systems gave ten-fold and three-fold improvements, respectively, in protein extraction yield as compared
to the enzyme-free blank procedure. The combined action of xylanase and cellulose on protein extraction from Palmaria palmata does not significantly improve protein yield. The best overall protein yield for P. palmata is for P. palmata/xylanase with a 14-h incubation time. This study shows the interest in the use of a polysaccharidase mixture for improving
protein extractibility from certain rhodophytes. This biotechnology approach, adapted from procedures for protoplast production
or enzymatic liquefaction of higher plants, could be tested as an alternative method to obtain proteins from seaweeds of nutritional
interest. 相似文献