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1.
1. The insoluble residue and material present in the aqueous layers resulting from treatment of cell walls of Pseudomonas aeruginosa with aqueous phenol were examined. 2. The products (fractions AqI and AqII) isolated from the aqueous layers from the first and second extractions respectively account for approx. 25% and 12% of the cell wall and consist of both lipopolysaccharide and muropeptide. 3. The lipid part of the lipopolysaccharide is qualitatively similar to the corresponding material (lipid A) from other Gram-negative organisms, as is the polysaccharide part. 4. The insoluble residue (fraction R) contains sacculi, which also occur in fraction AqII. On hydrolysis, the sacculi yield glucosamine, muramic acid, alanine, glutamic acid and 2,6-diaminopimelic acid, together with small amounts of lysine, and they are therefore similar to the murein sacculi of other Gram-negative organisms. Fraction R also contains substantial amounts of protein, which differs from that obtained from the phenol layer. 5. The possible association or aggregation of lipopolysaccharide, murein and murein sacculi is discussed.  相似文献   

2.
High molecular weight material recovered from the culture filtrate of cell suspension cultured Pyrus communis was composed of 81% carbohydrate, 13% protein and 5% inorganic material. This material was separated into three fractions (one neutral (Fraction A) and two acidic (Fractions B and C)), by anion-exchange chromatography on DEAE-Sepharose CL-6B using a gradient of imidazole-HCl at pH 7.0. The monosaccharide and linkage composition of each fraction was determined after carboxyl reduction of uronic acid residues. From the combined results of the carbohydrate analyses, we conclude that the high molecular weight extracellular material consists of three major and two minor polysaccharides: a (fucogalacto)xyloglucan (36%) in the unbound neutral Fraction A; a type II arabinogalactan (as an arabinogalactan-protein, 29%) and an acidic (glucurono)arabinoxylan (2%) in Fraction B; and a galacturonan (33%) and a trace of heteromannan in Fraction C. The main amino acids in the proteins were Glx, Thr, Ser, Hyp/Pro and Gly. Further separation of Fraction B by solvent partition, SDS-PAGE and analysis by LC-MS/MS identified the major proteins as two chitanases, two thaumatin-like proteins, a beta-1,3-glucanase, an extracellular dermal glycoprotein and a pathogenesis-related protein.  相似文献   

3.
Low-phenylalanine-peptides for dietotherapy of phenylketonuria (PKU) were prepared from soybean protein isolate. Soluble fraction of soybean protein isolate was hydrolysed by alpha-chymotrypsin then followed by carboxypeptidase-A. Molecular weight distribution and amino acid analysis were made on the resultant polypeptides. The chymotrypsin hydrolysate was divided into two fractions, Fraction I (molecular weight greater than 2500) and Fraction II (molecular weight between 1000 and 2500). The phenylalanine content of Fraction I (3.1%) was lower than that of Fraction II (5%), indicating the nonuniform distribution of phenylalanine in soy bean protein. Carboxypeptidase hydrolysis of Fraction I further reduced the phenylalanine concentration to 2.3%, approximately half of the original concentration in soybean protein isolate.  相似文献   

4.
Studies of the cell walls of Schizophyllum commune   总被引:1,自引:0,他引:1  
Mechanically isolated cell wall materials of eight strains of Schizophyllum commune were studied by chemical and enzymatic procedures. Isolated wall material of each strain was separated by chemical methods into three fractions: A (cold alkali-soluble, , amorphous), B (warm alkali-soluble, amorphous), and C (alkali-insoluble, retaining appearance of hyphal fragments). Chemical tests indicated the presence of chitin in Fraction C and the absence of cellulose, lignin and pectic substances from all fractions. Analyses of acid hydrolysates indicated the presence of glucose in Fractions A, B and C, of hexosamine in Fraction C and the absence of galactose, mannose, 6-deoxyhexoses, xylose and other pentoses from all fractions. Unfractionated material, Fraction A and Fraction B were slightly attacked by commercial cellulase whereas Fraction C was heavily attacked. Commercial chitinase by itself did not attack Fraction C or unfractionated material to a significant extent. In the presence of cellulase, it was active upon Fraction C. Qualitative differences in cell wall composition between strains were not detected; however, quantitative differences were observed in the proportion of Fraction A and Fraction C as well as in the amount of the various breakdown products in certain strains. It is visualized that the cell wall of this fungus consists of a core of chitin covered by or intermeshed with glucose-containing polymers.  相似文献   

5.
Hemicellulosic polymers of cell walls of zea coleoptiles   总被引:11,自引:11,他引:0  
Hemicellulosic polymers comprised about 43% of the primary walls of Zea mays L. cv WF9 × Bear 38 coleoptiles; these polymers were separated by an alkali-gradient into three major fractions. Fraction 1 (GAX I) was solubilized from walls with 0.01 to 0.045 n KOH and consisted of novel glucuronoarabino(galacto)xylans. Nearly six of every seven residues of these xylans were substituted predominantly with single arabinosyl sidegroups. Fraction 2 (GAX II), material released by 0.45 to 0.8 n KOH, was also enriched with glucuronoarabinoxylan, but only two of every three xylose residues was substituted. This xylan was similar to those found in Zea and other Graminaceous species. Both of these xylan fractions contained uronic acid, terminal- and 4-linked galactosyl, and small amounts of 2-, 3-, 5-, and 3,5-linked arabinosyl units. Fraction 3 (MG-GAX) was released by 2.0 to 3.0 n KOH and consisted of about 60% mixed-linked glucan and about 40% glucuronoarabinoxylan. This fraction represented about half of the total hemicellulosic material of the primary walls of these coleoptiles.  相似文献   

6.
Relatively large-scale production and purification of meningopneumonitis organisms was developed for chemical and immunological studies on cell walls of the infectious dense forms. By disruption of purified organisms with glass beads in a Mickle shaker, highly purified preparations of cell walls were obtained by sucrose density gradient centrifugation, enzyme digestion, and sodium dodecyl sulfate treatment. The dry-weight recovery of purified cell walls from intact organisms was about 13%. When (32)P-labeled preparations of cell walls were fractionated into acid-soluble, lipid, ribonucleic acid (RNA), deoxyribonucleic (DNA), and residual fractions, about 80% of the (32)P in cell wall preparations was recovered in the phospholipid fraction, which corresponded to about 3% of the total phospholipid in the intact organisms. About 7% of the (32)P in purified cell walls was recovered in the RNA and DNA fractions respectively, but this corresponds to only about 0.4% of the (32)P found in those fractions in intact organisms. From dry-weight determinations, it was calculated that the purified cell wall preparations contained only 0.6% total nucleic acids, and these are probably not true cell wall constituents. These cell walls contained 70 to 75% protein, corresponding to about 14% of the protein in intact organisms. Amino acid analysis of these protein showed the existence of all common amino acids, glucosamine, and galactosamine. However, no muramic acid was detected by the methods employed.  相似文献   

7.
A fraction containing a variety of low molecular weight substances was extracted into 80% aqueous acetone from both a colicin E2-treated cell culture of Escherichia coli and an untreated one. The extract was divided into five fractions by Sephadex G15 chromatography. One of them, Fraction B, was separated into three subfractions by Sephadex G10 chromatography. Two subfractions, Fraction BI and Fraction BII, were further fractionated by several chromatographic systems. DNA was incubated with an aliquot from each of these fractions and was then analyzed by sedimentation in an alkaline sucrose density gradient. The activity which caused a decrease in the sedimentation coefficient of the DNA was found in some of these fractions. The activity from colicin E2-treated cells was compared with that from untreated ones. It was revealed that colicin E2 induces some increases in the activity toward DNA in one of the subfractions, Fraction BI, and also causes the appearance of a new species in another fraction, Fraction BII, which potentiates the activity in Fraction BI. These colicin E2-induced changes appeared at 5 min after the addition of colicin E2. The possible significance of such reactions for the action of colicin E2 are discussed.  相似文献   

8.
The delipidated protein component of bovine serum high density lipoprotein was fractionated by gel filtration on a Sephadex G-150 column (equilibrated with buffer containing 6 M urea) into three fractions: I, II and III. Fractions I and II together constitute 88% of all the protein weight of bovine high density lipoprotein, whereas fraction III accounts for the remaining 12%. Analysis of the fractions by sodium dodecyl sulfate-polyacrylamide electrophoresis reveals that fraction I consists mostly of aggregated forms of fraction II and some higher molecular weight species, probably irreversible aggregates of fraction II. The irreversible aggregates are apparently formed during the delipidation procedure or upon aging of the lipoprotein. The major protein component of the high density bovine lipoprotein is found in fraction II; it has a molecular weight of 27 000 plus or minus 1500 and appears to be homogeneous by several physicochemical criteria. The amino acid composition of fractions I and II are essentially identical; their spectral properties, including absorption, fluorescence, and circular dichroism spectra, are similar; however, fraction I appears to contain traces of oxidized lipid and more secondary alpha-helical organization than fraction II. By comparison with the intact lipoprotein, which contains about 65% of alpha-helical structure, fractions I and II have diminished alpha-helical organization, 55% and 43%, respectively. Fraction III, on sodium dodecyl sulfate-polyacrylamide electrophoresis, separates into two protein bands of equivalent intensity, having molecular weights around 13 000 and 11 000. Fraction III is markedly distinct from the other two, in amino acid composition and spectral properties, especially in its red-shifted fluorescence and very low content of alpha-helical structure. The protein composition of bovine serum high density lipoprotein is compared with recently published results for high density lipoprotein apoproteins of man, chimpanzee, rhesus monkey, pig and rat. Similarities and differences are discussed in terms of possible evolutionary and functional factors.  相似文献   

9.
Soluble endogenous inhibitory activities for glycoprotein: alpha (1-2) and alpha (1-3) fucosyltransferases are demonstrated in rat small intestinal cytosol. These inhibitors are retained on DEAE-cellulose and are eluted as two fractions A and B. Fraction B is non dialyzable, heat stable and pronase-resistant and consists probably of poly-nucleotides. Fraction A is also non-dialyzable, but is thermolabile and pronase-sensitive, suggesting that it contains proteins. The inhibition of fucosyltransferase activity by fraction A is competitive for GDP-fucose and non-competitive for the glycoprotein substrate. Inhibition is not due to interfering enzymatic activities (glycosyl-nucleotide pyrophosphatases, glycosidases or proteases) and is reversible. This protein inhibitor, with a molecular weight of 60,000, is found only in the intestine and the pancreas and appears to be different from the previously reported inhibitors of brain glycolipid glycosyltransferases.  相似文献   

10.
A fractionation of Chromatium vinosum into an outer layer (cell wall) and three intracellular membrane fractions by isopycnic sucrose density centrifugation of a total membrane fraction obtained by lysis of lysozyme-EDTA spheroplasts is decribed. The three intracellular fractions (I, II, and III) have apparent densities of 1.11, 1.14, and 1.16, respectively, and contain the bulk of the photosynthetic pigments. Fraction II is enriched in bacteriochlorophyll and contains about 49% of the total membrane protein and 60% of the membrane bacteriochlorophyll. The outer membrane fraction (IV, cell wall) has a density of 1.23 and contains 5% of the membrane protein and 0.8% of the bacteriochlorophyll. Fraction I is enriched in lipids and phosphorus and has only a trace of diaminopimelate (DAP). Fractions II and III both contain a significant content of DAP. Fraction IV has no DAP, but has a fatty acid composition similar to that of the envelope fraction. Electrophoresis of the fractions on sodium dodecylsulfate-containing gels yielded from 8–13 bands of protein. Fractions I, II, and III contained the same series of unique proteins, while fraction IV contained another group of unique proteins. In fraction IV the bulk of the proteins traveled in one band with a molecular weight of 41,500. Examination of the fractions and whole spheroplasts in the electron microscope showed that fractions I, II and III were composed of large membrane structures in the form of membrane reticulum with bud-like appendages, and elongated flattened tubes. Fraction IV was composed of large ovoid structures which were seen to lie on the outer surface of the whole spheroplasts. These results suggest that the normal in vivo state of the intracellular membranes is that of an interconnected series of tubules and vesicles extending throughout the cell cytoplasm.  相似文献   

11.
Naegeli amylodextrin is the insoluble residue remaining after prolonged treatment of native starch granules with strong aqueous acid. The Naegeli amylodextrin from waxy maize starch was separated by gel chromatography on Sephadex G-50 into three fractions. Although the fractions were heterogeneous, their average structures were examined by enzymic degradation with porcine-pancreactic alpha amylase, beta-amylase, and pullulanase. The results show that Fraction I (highest molecular weight) has complex branching, Fraction II (major component, d.p. ~25) contains about one branch per molecule, and Fraction III (d.p. ~12) is mostly linear. Formation of these acid-resistant fractions may be explained as arising from a cluster model of amylopectin in which the outer chains are in a double-helical, crystalline arrangement.  相似文献   

12.
Three fractions of poly(A)-containing RNA were separated from total rat liver RNA using poly(U)-Sepharose 4B affinity chromatography. The poly(A)-containing RNA fractions were released by thermal elution. Fraction 1, eluted under the mildest conditions, and had poly(A) tracts of approx. 200 AMP units in length which appeared to be associated with poly(U) sequences of 20-50 UMP in length. Fraction 1 appeared to be present mainly in the nucleus and, its size distribution was similar to that of fractions 2 and 3. Fractions 2 and 3 eluted at higher temperatures and were associated mainly with polysomal and microsomal fractions. Poly(U) sequences were absent in fractions 2 and 3 while their poly(A) sequences had a size distribution characteristic of those reported in the mRNA of other organisms.  相似文献   

13.
The Na+ channel activity (tetrodotoxin sensitive 22Na+ flux induced by veratridine and/or anemone toxin II) was studied in two fractions of brain cell plasma membranes, named A and B, isolated by the method of Gray and Whittaker ((1962) J. Anat. 96, 79–87) from rats 5, 10, 30 and 60 days old. The 22Na+ flux was measured in membrane vesicles formed by the isolated membranes, in the absence of drugs (control), in the presence of veratridine, and in the presence of veratridine plus tetrodotoxin. Fraction A consists primarily of neuronal and glial membranes in rats of 5 and 10 days of age, while in the older rats this fraction becomes enriched in myelin. In Fraction A of 5-day-old and 10-day-old rats, veratridine (25 μM) increases the 22Na+ flux 2.4- and 1.6-fold, respectively, and the increment continues to diminish with age, until it becomes negligible in the 60-day-old rats. Fraction B consists of synaptosomes and membrane vesicles, and at the four ages studied veratridine (25 μM) causes an increment of the 22Na+ flux of about 2.5-fold. Fractions A and B from 10-day-old rats, and Fraction B from 60-day-old rats, which are sensitive to veratridine, also respond to anemone toxin II. When veratridine is used in presence of anemone toxin II (0.5 μM), the K0.5 for veratridine is diminished and the maximum 22Na+ flux is increased. The increments of 22Na+ flux caused by veratridine and/or anemone toxin II in Fractions A and B are blocked by tetrodotoxin (K0.5 approx. 5 nM). Fraction A from 60-day-old rats could be subfractionated by osmotic shock and sucrose gradient centrifugation to obtain three subfractions, two of which are enriched in axolemma and display Na+ chennel activity. The other subfraction is enriched in myelin and shows no Na+ channel actiivty. The plasma membrane preparations from young rats (up to 10 days) are devoid of myelin and are useful for studies of Na+ channel activity.  相似文献   

14.
Androgen receptor was immunolocalized in the epididymal epithelium of rams and in isolated cells using an antibody against a synthetic polypeptide representing a portion of the androgen receptor. Immunostaining was predominant in the epithelium in tissue sections. Concentrations of androgen receptor were determined in cells from the central caput, distal caput, and central corpus epididymidis enzymically dissociated and elutriated to provide two fractions. On the average (n = 18), Fraction I contained 8% principal cells while Fraction II contained 71% principal cells; the stromal cells in each fraction were primarily smooth muscle and fibroblasts. For each sample, the number of DHT receptors (fmol) per 10(6) total cells was greater in Fraction II than in Fraction I. Few cells in Fraction I were immunostained for androgen receptor, whereas most cells in Fraction II were intensely stained. The numbers of DHT receptors per cell, or per principal cell, were similar for the central caput and distal caput, but lower in the central corpus epididymidis. The results support our hypothesis that most epididymal DHT receptors are localized in principal cells and confirm that the region between the central caput and proximal corpus of the ram epididymis is most dependent on androgen stimulation.  相似文献   

15.
Cellulose and xyloglucan (XG) assemble to form the cellulose/XG network, which is considered to be the dominant load-bearing structure in the growing cell walls of non-graminaceous land plants. We have extended the most commonly accepted model for the macromolecular organization of XG in this network, based on the structural and quantitative analysis of three distinct XG fractions that can be differentially extracted from the cell walls isolated from etiolated pea stems. Approximately 8% of the dry weight of these cell walls consists of XG that can be solubilized by treatment of the walls with a XG-specific endoglucanase (XEG). This material corresponds to an enzyme-susceptible XG domain, proposed to form the cross-links between cellulose microfibrils. Another 10% of the cell wall consists of XG that can be solubilized by concentrated KOH after XEG treatment. This material constitutes another XG domain, proposed to be closely associated with the surface of the cellulose microfibrils. An additional 3% of the cell wall consists of XG that can be solubilized only when the XEG- and KOH-treated cell walls are treated with cellulase. This material constitutes a third XG domain, proposed to be entrapped within or between cellulose microfibrils. Analysis of the three fractions indicates that metabolism is essentially limited to the enzyme-susceptible domain. These results support the hypothesis that enzyme-catalyzed modification of XG cross-links in the cellulose/XG network is required for the growth and development of the primary plant cell wall, and demonstrate that the structural consequences of these metabolic events can be analyzed in detail.  相似文献   

16.
Ejaculates from 3 young boars were collected on 4 occasions as a series of separate 15-ml fractions. The contribution of different fractions of these ejaculates to observed variability in the quality of the semen when used for IVF was then determined. On the basis of sperm concentration, 3 fractions representing the first peak concentration (Fraction 1), the lowest sperm concentration after Fraction 1 (Fraction 2), and the second peak concentration (Fraction 3) were selected for analysis in vitro. Oocyte-cumulus-granulosa cell complexes were obtained by dissection from slaughterhouse ovaries. In vitro matured oocytes were randomly assigned for fertilization by the 3 semen samples from each boar. Sperm concentration was the same in all the samples during prefertilization incubation, while the final concentration for fertilization was 5 x 10(5) sperm/ml. Data were analysed using ANOVA for a split-plot design. In the presence of fraction effects, Student-Newman-Keuls (SNK) test was used for multiple comparison of treatment means. Oocyte penetration rates differed among fractions (P = 0.001) and varied from 69 to 100% (mean 95.7%) for Fraction 1, from 0 to 100% (mean 53.3%) for Fraction 2, and from 50to 100% (mean 89.9%) for Fraction 3. There were also differences in male pronuclear formation rate (P = 0.028; mean 27.6, 9.3 and 16.4% for Fractions 1, 2 and 3, respectively); in the rate of polyspermy (P = 0.0001; mean 92.3, 31.9 and 76.3% for Fractions 1, 2 and 3, respectively); and in the number of penetrated spermatozoa per oocyte P = 0.002; mean 5.58, 1.94 and 4.07 for Fractions 1, 2, and 3, respectively). The first peak concentration of semen (Fraction 1) showed superiority in fertilizing ability and less variability in penetration rate from replicate to replicate compared with the other 2 fractions. By multiple comparison, Boar 1 showed higher rates of penetration (P < 0.05), male pronuclear formation (P < 0.05) and polyspermy (P < 0.05) than the other 2 boars. There was no fraction-by-boar interaction. The IVM-IVF system adopted proved to be a promising method for boar semen evaluation.  相似文献   

17.
Enzymatic heme oxygenase activity has been partially purified from extracts of the unicellular red alga Cyanidium caldarium, and the macromolecular components have been separated into three protein fractions, referred to as Fractions I, II, and III, by serial column chromatography through DEAE-cellulose and Reactive Blue 2-Sepharose. Fraction I is retained by DEAE-cellulose at low salt concentration and eluted by 1 M NaCl. Fraction II is retained by Blue Sepharose at low salt concentration and eluted by 1 M NaCl. Fraction III is retained on 2',5'-ADP-agarose and eluted by 1 mM NADPH, while Fraction II is not retained on ADP-agarose. Fractions I-III, have Mr values of 22,000, 38,000, and 37,000, respectively (all +/- 2,000), as determined by Sephadex gel filtration chromatography. In vitro heme oxygenase activity requires the presence of all three fractions, plus substrate, O2, reduced pyridine nucleotide, and another reductant. Ascorbate, isoascorbate, and phenylenediamine serve equally well as the second reductant, but hydroquinone can also be used, with lower activity resulting. Fractions I-III are heat sensitive and inactive by Pronase digestion. Fraction I has a visible absorption spectrum similar to that of ferredoxin and is bleached by dithionite reduction or incubation with p-hydroxymercuribenzoate. Fraction I can be replaced by commercially available ferredoxin derived from the red alga Porphyra umbilicalis, and to a smaller extent, by spinach ferredoxin. Fraction III contains ferredoxin-linked cytochrome c reductase activity and can be partially replaced by spinach ferredoxin-NADP+ oxidoreductase. Reconstituted heme oxygenase and ferredoxin-linked cytochrome c reductase activities are both abolished if Fraction I or III is preincubated with 0.1 mM p-hydroxymercuribenzoate, but heme oxygenase activity is only slightly affected if Fraction II is preincubated with p-hydroxymercuribenzoate. Preincubation of Fraction II with 0.5 mM diethylpyrocarbonate inactivates heme oxygenase in the reconstituted system, and 10 microM mesohemin partially protects this Fraction against diethylpyrocarbonate inactivation. Algal heme oxygenase is inhibited 80% by 2 microM Sn-protoporphyrin even in the presence of 20 microM mesohemin. Fraction II is rate limiting in unfractionated and reconstituted incubation mixtures. None of the three cell fractions could be replaced by bovine spleen microsomal heme oxygenase or NADPH-cytochrome P450 reductase.  相似文献   

18.
The cortical and medullary cells of Kappaphycus alvarezii fractions were screened by wet sieving after aqueous extraction of carrageenans. The cell populations obtained showed a clear partition between these two cell types. The main monosaccharide in hydro-insoluble cell walls was cellulosic glucose (70% dry weight), the crystallinity of which was shown torange from 20% in the cortical cells to 45% in the large medullary cells (over 250 μm diameter). Minor monosaccharides in the insoluble fraction were galactose, 3,6-anhydrogalactose (indicating presence of residual carrageenans), mannose and xylose. However, the major part of the remaining galactose probably originated from another galactoglycan strongly linked to insoluble polymers in the large medullarycell walls. The mannose concentration was maximum in the cortical cells and decreased with increasing size of the medullary cells. Thus, besides cellulose, two other types of polysaccharides were detected in insolublecell walls, mannoglycans and galactoglycans in cortical and medullary cellwalls, respectively. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

19.
Vesicular fragments of Golgi apparatus, smooth- and rough-surfaced microsomes from rat liver are differently partitioned in aqueous polymer two-phase systems consisting of dextran, polyethylene glycol, and sodium phosphate buffer. At a given polymer concentration, the amount of material partitioned in the top phase increases in the following order: rough microsomes less than smooth microsomes less than Golgi fragments. Counter-current distribution of Golgi fragments in the system consisting of 6.8% (w/w) dextran T500 and 6.8% polyethylene glycol 4,000 results in the separation of the fragments into three fractions; i.e. Fractions I, II, and III. NADH- and NADPH-cytochrome c reductase activities are detected almost exclusively in Fraction I, whereas the activities of galactosyltransferase, acid phosphatase, 5'-nucleotidase, and thiamine pyrophosphatase are maximal in Fraction III and minimal in Fraction I. The distribution of these enzymes suggests that Fraction I is similar to, though not identical with, microsomes, Fraction III resembles plasma membrane and lysosomes, and Fraction II is between the two. It is concluded that NADH- and NADPH-cytochrome c reductases are localized in a restricted region of the Golgi structure and that intra-Golgi differentiation seems to proceed in a discontinuous manner.  相似文献   

20.
Two protein fractions with activity as α-galactosidase (EC 3.2.1.22) and α-arabinosidase (EC 3.2.1.55), respectively, were identified in the proteins of cell wall of Cicer arietinum L. cv. Castellana extracted with 3 M LiCl. These fractions were partially purified by gel filtration chromatography (Bio Gel P-150), increasing the specific arabinosidase activity 57-fold and the α-galactosidase activity 6-fold. Other protein fractions with glucosidase (EC 3.2.1.21) and glucanase (EC 3.2.1.6) activity also appeared. According to earlier authors, α-arabinosidases and α-galactosidases are related to alterations in linkages occurring in cell walls, since the enzymes are able to hydrolyze isolated wall polymers. However, our preparations hydrolyze intact cell walls only to a very limited extent, such that their participation in the autolytic processes of cell walls can be ruled out.  相似文献   

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