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K Takeda

Publications and source records attributed to K Takeda.

At least 523 records · Page 29Linked to original sources
PubMed1997

Targeted disruption of the mouse Stat3 gene leads to early embryonic lethality.

Signal transducer and activator of transcription (STAT) proteins have been shown to mediate biological actions in response to cytokines. Stat3, a member of the STAT family, is activated by a variety of cytokines, including the interleukin 6 family of cytokines, leptin, granulocyte colony-stimulating factor, and epidermal growth factor. To address the biological function of Stat3, we generated mice deficient in Stat3 by gene targeting. No viable Stat3-deficient mice could be obtained from heterozygote intercross. Analysis of embryos at several gestation times revealed that Stat3-deficient embryos showed a rapid degeneration between embryonic days 6.5 and 7.5, although they developed into the egg cylinder stage until embryonic day 6.0. These results demonstrate that Stat3 is essential for the early development of mouse embryos.

Animals↗
PubMed1997

Neuropeptide Y modulates ATP-induced increases in internal calcium via the adenylate cyclase/protein kinase A system in a human neuroblastoma cell line.

The modulatory effects of neuropeptide Y (NPY) on ATP-induced increases in cytosolic free-calcium concentration ([Ca2+]i) were investigated in the CHP-234 human neuroblastoma cell line. Pretreatment of cells with 100 nM NPY potentiated the increase in [Ca2+]i evoked subsequently by 20 microM ATP, compared with initial application of ATP in a control experiment, whereas a similar pretreatment with 1 microM NPY attenuated the subsequent response to ATP. Both actions of NPY were completely blocked by H-89 [N-[2-((3-(4-bromo-phenyl)-2-propenyl)-amino)-ethyl]-5 isoquinoline sulphonamide dihydrochloride], a selective antagonist of protein kinase A. The effects of 100 nM NPY were mimicked by H-89, while forskolin and 8-Br-cAMP mimicked the effects of 1 microM NPY. Both basal and forskolin-stimulated cAMP levels were inhibited by 100 nM NPY and by 100 nM NPY(13-36), a selective agonist of the NPY Y2-receptor subtype. In contrast, at 1 microM such inhibition was not observed for either NPY or NPY(13-36). It is concluded that NPY has a biphasic modulatory effect on increases in [Ca2+]i produced by ATP, which probably involves the cAMP/protein kinase A cascade.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1997

Graft persistence effectively induces and maintains donor-specific unresponsiveness.

BACKGROUND: In the present study we attempted to evaluate the role of the graft as an alloantigen in induction and maintenance of donor-specific prolongation of allograft survival by short course(s) of FK506 treatment in rat heart transplantation. Materials and methods. In the WKA/Qdj-to-LEW combination group, FK506 (3 mg/kg/day, 7 days, s.c.) was administered from Day 0 after cardiac transplantation. A second WKA/ Qdj cardiac graft was transplanted on Day 14 into the LEW recipient after removal of the first graft on Day 3 or Day 7. In other groups an additional course of FK506 (3 mg/kg/day, 7 days, s.c.) was given from Day 35. A second WKA/Qdj cardiac graft was transplanted on Day 49 into the LEW recipient after removal of the first graft on Day 7 or Day 28. RESULTS: A short course of FK506 treatment allowed for survival prolongation of a cardiac allograft [mean survival time (MST) = 42.8 days]. Removal of the first graft on Day 7 (MST = 16.4 days) but not on Day 3 (MST = 10.2 days) caused donor-specific prolongation of the second allograft survival, which was significantly shorter than that in the recipient without the graftectomy (MST = 32.8 days). When graftectomy was performed on Day 3, there were immunohistochemically detectable levels of donor class II expressing cells in the recipient spleen on Day 7, indicating that the presence of the graft more effectively induced unresponsiveness than microchimerism alone. The additional course of FK506 treatment on Day 35 maintained graft survival (MST > 90.6 days). Removal of the first graft on Day 7 (MST = 13.5 days) or Day 28 (MST = 24.7 days) did not show significant prolongation of the second allograft survival, whereas significant survival prolongation of the second graft was observed in the recipient without the graftectomy (MST = 38.8 days). However, marked survival prolongation of the second donor-specific allograft in half of the recipients that had received the second course of FK506 treatment after graftectomy on Day 28 indicates that residual donor antigen can function as tolerizing antigen with an FK506 supplement. CONCLUSIONS: We concluded that the persistence of a graft more effectively induces and maintains donor-specific unresponsiveness than does the chimeric state of graft-derived cells alone under immunosuppression by FK506 in the rat heart transplantation model.

Animals↗
PubMed1997

Quantitative analysis of scatter- and attenuation-compensated dynamic single-photon emission tomography for functional hepatic imaging with a receptor-binding radiopharmaceutical.

A new method for quantitative liver study was developed using the tracer technetium-99m diethylene triamine penta-acetic acid-galactosyl human serum albumin (99mTc-GSA), an analog ligand of the asialoglycoprotein receptor, which is a hepatocyte surface receptor specific for galactose-terminated glycoproteins. For quantitative dynamic single-photon emission tomographic (SPET) studies, attenuation compensation using transmission computed tomography (TCT) and the triple energy window (TEW) scatter compensation method were evaluated. As the TCT source, we used an uncollimated multi-tube source with the TEW scatter compensation method. To verify the accuracy of cross-calibrated SPET values as compared with measured radioactivities, we performed SPET of a cylindrical water pool phantom which contains seven hot rods filled with different concentrations of 99mTc activities, simulating the scan conditions in human studies. The results of the phantom studies showed good linearity and accuracy of the SPET values, with R2=0.993 and a regression line of y=0.941x+5.48. From the analysis of a kinetic model based on a one-compartment model, focussing on the initial stage of several minutes after 99mTc-GSA injection and taking the physiological expression presented in a three-compartment analysis into account, we introduced the Rutland equation (Patlak plot) in the 99mTc-GSA study by which the overall and regional effective hepatic blood flow (EHBF) and hepatic blood pool volume were determined. Preliminary clinical evaluations were performed for four normal male subjects (23-35 years of age) and one patient. Forty sequential 30-s dynamic SPET acquisitions were obtained for a period of 20 min following the intravenous injection of 99mTc-GSA with venous blood sampling at 10 min. After scatter compensation, the SPET images were reconstructed with attenuation compensation using an attenuation map obtained from TCT. The average normal value for the total EHBF was 468+/-83 ml/min and that for the hepatic blood pool volume, 777+/-123 ml. Functional images of the distribution of regional values of EHBF (ml/min/voxel) and hepatic blood pool volume (ml/voxel) were also generated corresponding to the original SPET images. The EHBF images showed regional liver function, higher in the right lobe than the left lobe in the normal cases, and the heptic blood pool volume images showed the distribution of intensified high values along major vascular structures. Receptor imaging with 99mTc-GSA using the Rutland method and dynamic SPET with scatter and attenuation compensation is an effective technique that allows the evaluation of total and regional hepatic functional parameters (EHBF, hepatic blood pool) in vivo.

Adult↗
PubMed1997

STAT6: its role in interleukin 4-mediated biological functions.

Interleukin (IL) 4 is known to be a cytokine which plays a central role in the regulation of immune response. Studies on cytokine signal transduction have clarified the mechanism by which IL4 exerts its functions. Two cytoplasmic proteins, signal transducer and activator of transcription (STAT) 6 and IL4-induced phosphotyrosine substrate/insulin receptor substrate 2 (4PS/IRS2), are activated in IL4 signal transduction. Recent studies from STAT6-deficient mice have revealed the essential role of STAT6 in IL4-mediated biological actions. In addition, STAT6 has also been demonstrated to be important for the functions mediated by IL13, which is related to IL4. IL4 and IL13 have been shown to induce the production of IgE, which is a major mediator in an allergic response. These findings indicate that STAT6 activation is involved in IL4- and IL13-mediated disorders such as allergy.

Animals↗
PubMed1997

Localization of 2',5'-oligoadenylate synthetase and the enhancement of its activity with recombinant interferon-alpha A/D in the mouse brain.

Although the expression of 2',5'-oligoadenylate synthetase (2-5AS) is induced by interferon (IFN), low constitutive levels can be detected in animals that have not been treated with IFN. In order to clarify which cells express 2-5AS in the mouse brain, the distribution of this enzyme in the brains of both normal healthy mice and mice treated with recombinant human IFN-alpha A/D was studied by Western blotting and immunohistochemistry, using a specific monoclonal antibody. On the Western blots, the antibody to 42-kD 2-5AS reacted slightly with extracts from the telencephalon, cerebellum, diencephalon, and medulla oblongata of normal mouse brain. 42-kD 2-5AS was predominantly found in the ependymal cells and epithelium of the choroid plexus, and to a lesser degree in neurons and glial cells. Injection of recombinant human IFN-alpha A/D into the left lateral ventricle enhanced the activity of the enzyme in the telencephalon, cerebellum, diencephalon, and medulla oblongata, but did not change the immunohistochemical localization of the enzyme. Direct injection of the IFN into the cortex of the telencephalon enhanced the activity of 2-5AS in all parts of the brain and immunoreactivity was observed in the neurons and glial cells surrounding the injection site. These data indicate that 42-kD 2-5AS activity in the mouse brain is enhanced by the injection of recombinant human IFN-alpha A/D either into the left lateral ventricle or cortex of the telencephalon. Expression of 42-kD 2-5AS in ependymal cells and epithelium of the choroid plexus may prevent viral infections in the brain.

2',5'-Oligoadenylate Synthetase↗
PubMed1997

Reduction of insulin resistance attenuates the development of hypertension in sucrose-fed SHR.

We examined the effect of pioglitazone, a thiazolidinedione derivative that increases insulin sensitivity without increasing insulin secretion, on the development and maintenance of hypertension in sucrose-fed SHR. Nine-week-old male SHR received 12% sucrose dissolved in tap water as drinking water. For 5 weeks, half of the rats were given regular rat chow, and the rest were fed with rat chow containing 0.03% pioglitazone. In week 6, blood glucose and plasma insulin levels were examined before and after oral glucose administration by gavage. Sucrose treatment elicited a significant elevation of systolic blood pressure 3 weeks after the beginning of treatment; pioglitazone treatment attenuated this elevation. The insulin resistance and hyperinsulinemia observed in sucrose-fed SHR were prevented by pioglitazone treatment. Pioglitazone treatment also significantly reduced the urinary excretion of catecholamines and plasma renin activity, both of which were significantly greater in sucrose-fed SHR than in control SHR. Along with improving insulin sensitivity, pioglitazone treatment also attenuated the development of hypertension in SHR fed the regular rat chow, but not in WKY rats. These results indicate that insulin resistance and hyperinsulinemia play an important role in the development of hypertension in SHR probably through the activation of the renin-angiotensin system and sympathetic nervous outflow. This study also shows that chronic sucrose treatment exacerbated the development of hypertension through these mechanisms, precipitating insulin resistance.

Animals↗
PubMed1997

Juvenile hemangioma of the testis: analysis of expression of angiogenic factors.

We present a case of juvenile hemangioma of the testis associated with hemangiomas of the liver and skin. The testicular hemangioma appeared to progress after therapy with interferon alpha-2a (IFN alpha-2a), whereas the liver and skin hemangiomas regressed. Analysis of growth factors responsible for proliferation of hemangioma revealed that the tumor expressed vascular endothelial growth factor but not basic fibroblast growth factor (bFGF), which is reported to be inhibited by IFN alpha-2a. This finding suggests that a possible explanation for the inadequate efficacy of IFN alpha-2a for testicular hemangioma is a lack of bFGF expression.

Angiogenesis Inducing Agents↗
PubMed1997

High dose rate endobronchial brachytherapy using a new applicator.

BACKGROUND AND PURPOSE: To obtain adequate spatial dose distribution for endobronchial brachytherapy, we applied reference dose points according to the bronchial diameter. For this purpose, we devised a new applicator of which the source transfer tube is contained in the center of the lumen for high dose rate (HDR) brachytherapy. MATERIALS AND METHODS: Thirty-nine patients with endobronchial cancer underwent endobronchial brachytherapy using an HDR afterloading machine with an Ir-192 source. In the nine patients treated with curative intent, treatment consisted of external beam radiotherapy with 40-60 Gy for 4-6 weeks and endobronchial brachytherapy with three fractions of 6 Gy. The 30 patients treated with palliative intent received one fraction of 10 Gy with or without external beam irradiation. The reference dose points were prescribed according to bronchial diameter, which was measured by the applicator's radiopaque wing expansion reflecting the bronchial caliber. RESULTS: The new applicator could be placed at the intended site in 37 lesions. Of 12 lesions which were treated with curative intent, eight (67%) disappeared after brachytherapy. The overall survival at 3 years of all patients and of the patients treated with curative intent was 22 and 64%, respectively. CONCLUSIONS: The source should be positioned in the center of the lumen; this technique is helpful in reducing side-effects caused by inhomogeneous dose distribution of endobronchial brachytherapy.

Adult↗
PubMed1997

Regeneration of the un-embolized liver parenchyma following portal vein embolization.

BACKGROUND/AIMS: Portal vein embolization (PVE) induces atrophy of the embolized hepatic parenchyma and hypertrophy of the un-embolized liver. It is important to predict hypertrophy of un-embolized liver following PVE to decide a subsequent tactics in patients with liver tumors. The hypertrophy following PVE was evaluated in reference to embolized liver volume and a preceding use of transcatheter hepatic arterial chemoembolization (HACE) in this study. METHODS: Thirty patients with liver tumors were studied. PVE was performed transhepatically. Ethanol (15-65 ml) was injected into portal veins, which perfused the liver segment bearing the tumor until occlusion. Embolization was performed at subsegmental portal branches in five patients, segmental branches in 11 patients and right portal veins in 14 patients. Twenty-three patients with underlying chronic liver disease and hepatocellular carcinoma (HCC) underwent PVE 2-6 weeks after HACE. The remaining seven patients without underlying chronic liver disease had bile duct cancer (6) or liver metastasis (1), and underwent PVE alone. Segmental volume in the liver was measured with computed tomography before and 4 weeks after PVE. RESULTS: The degree of hypertrophy showed a significant correlation with embolized liver volume (r=0.685, p<0.001). Increase in un-embolized liver volume was 2.4+/-5.8% with subsegmental embolization (NS), 15.2+/-6.4% with segmental embolization (p<0.01) and 46.5+/-18.8% with right PVE (p<0.001). In 14 patients with right PVE, degree of hypertrophy in seven patients with HACE was greater than that in seven patients without HACE (56.7+/-21.6% vs 36.4+/-7.4%; p<0.03). CONCLUSIONS: Hypertrophy of the un-embolized liver parenchyma following PVE was correlated with embolized liver volume and was augmented with combined use of HACE.

Adult↗
PubMed1997

Significance of the beta-subunit in the biogenesis of Na+/K(+)-ATPase.

This review summarizes our experiments on the significance of the beta-subunit in the functional expression of Na+/K(+)-ATPase. The beta-subunit acts like a receptor for the alpha-subunit in the biogenesis of Na+/K(+)-ATPase and facilitates the correct folding of the alpha-subunit in the membrane. The alpha-subunit synthesized in the absence of the beta-subunit is subjected to rapid degradation in the endoplasmic reticulum. Several assembly sites are assigned in the sequence of the beta-subunit from the cytoplasmic NH2-terminal domain to the extracellular COOH-terminus: the NH2-terminal region of the extracellular domain, the conservative proline in the third disulfide loop, the hydrophobic amino acid residues near the COOH-terminus and the cysteine residues forming the second and the third disulfide bridges. Upon assembly, the beta-subunit confers a resistance to trypsin on the alpha-subunit. The conformations induced in the alpha-subunit of Na+/K(+)-ATPase by Na+/K(+)- and H+/K(+)-ATPase beta-subunits are somehow different from each other and are named the NK-type and KH-type, respectively. The extracellular domain of the beta-subunit is involved in the folding of the alpha-subunit leading to trypsin-resistant conformations. The sequences from Cys150 to the COOH-terminus of the Na+/K(+)-ATPase beta-subunit and from Ile89 to the COOH-terminus of the H+/K(+)-ATPase beta-subunit are necessary to form trypsin-resistant conformations of the NK- and HK-type, respectively. The first disulfide loop of the extracellular domain of the beta-subunits is critical in the expression of functional Na+/K(+)-ATPase.

Amino Acid Sequence↗
PubMed1997

A novel mutation causing complete deficiency of thyroxine binding globulin.

OBJECTIVE: Thyroxine binding globulin (TBG) is a serum protein that transports thyroxine. Three naturally occurring mutations have been reported to produce complete deficiency of TBG (TBG-CD). The first to be reported was TBG-CD5 in caucasian families of French-Canadian origin and consists of substitutions in exons 2 and 3. TBG-CD of English ethnic origin (TBG-CD6) is characterized by a thymine deletion in codon 165 (exon 1). In Japanese families with TBG-CD (TBG-CDJ), a variant has been characterized with a deletion of the first base of the codon for amino acid 352 (exon 4) in the common type TBG. In this communication we report a new type of TBG-CD in a family of Japanese ethnic origin that is characterized by a single nucleotide substitution in place of two nucleotides in exon 1. This is an uncommon mutation which we have been unable to find in other genes. DESIGN: Exons of the TBG gene amplified by the polymerase chain reaction (PCR) were subcloned and sequenced. To examine for the presence of the same mutation in potentially affected individuals, we performed PCR using primer-directed mutagenesis or allele-specific amplification. PATIENTS: The index case was of Japanese ethnic origin, and was diagnosed as having TBG deficiency on the basis of undetectable serum TBG. The patient consented to this evaluation and the protocol was in accordance with IRB standards. MEASUREMENTS: Serum thyroid hormones, thyrotrophin binding inhibitory immunoglobulin and TBG concentrations were measured by conventional radio-immunoassay. Genomic DNA was extracted from white blood cells. RESULTS: In the index case exons 2, 3 and 4 were normal, but nucleotides 144 (cytosine) and 145 (thymine) in exon 1 were substituted with a single base (adenine) which induced a frame shift in the reading frame, resulting in an early stop codon at codon 51. The patient and his daughters were confirmed as having this mutation using primer-directed mutagenesis or allele-specific amplification. CONCLUSIONS: We have described a novel mutation in the TBG gene in a Japanese family. This results in a frame shift and premature stop codon, and was associated with undetectable serum TBG in the index case.

Exons↗
PubMed1997

Autologous killing by a population of intermediate T-cell receptor cells and its NK1.1+ and NK1.1- subsets, using Fas ligand/Fas molecules.

Self-reactive clones, estimated by anti-V beta monoclonal antibodies (mAb) in conjunction with the Mls system, are confined to a population of intermediate (int) T-cell receptor (TCR) (or CD3) cells (i.e. TCRint cells), but are not found among TCRhigh cells. The next questions to be answered are whether autologous killing is confined to TCRint cells and how such killing is mediated. In this study, 51Cr-labelled thymocytes of syngeneic or allogeneic origin were used as target cells (4-hr assay). When liver and splenic mononuclear cells (MNC) obtained from B6 mice were used as effector cells, prominent autologous killing was seen in liver MNC, but not splenic MNC. Such killing was not seen when thymocytes from B6-lpr/lpr mice (i.e. Fas-) were used as target cells, nor when liver MNC from MRL-gld/gld mice (i.e. Fas ligand-) were used as effector cells (target thymocytes of MRL(-)+/+ mice). Cell separation experiments using a cell sorter revealed that autologous killing was mediated for the most part by CD3int cells, while allogeneic killing was mediated entirely by natural killer (NK) cells, TCRint cells and TCRhigh cells. Among CD3int cells, the NK1.1+ subset (i.e. NK1.1+ T cells) manifested a higher level of autologous killing than did the NK1.1- subset. Consistent with the results of a functional assay, it was found by reverse-transcription-polymerase chain reaction (RT-PCR) assay that CD3int cells among liver MNC showed the expression of Fas ligand mRNA, while thymocytes expressed Fas mRNA. When class I major histocompatibility complex (MHC)- thymocytes (from beta 2-microglobulin-deficient mice) were used as target cells, NK cells, but not CD3int cells, showed potent cytotoxicity. These results suggest that autologous killing is a major function of TCRint cells with self-reactivity, and that such killing is mediated by means of Fas ligand/Fas molecules.

Animals↗
PubMed1997

Antimetastatic effect of NK1+ T cells on experimental haematogenous tumour metastases in the liver and lungs of mice.

Depletion of both natural killer 1.1+ (NK1+) intermediate alpha beta T-cell receptor (int T) cells and NK cells by in vivo treatment with anti-NK1 antibody greatly increased hepatic metastases of intravenously injected EL4 cells as well as pulmonary metastases of 3LL cells in C57BL/6 mice. However, depletion of NK cells alone by anti-asialo GM1 (AGM1) antibody treatment did not increase the metastases in either organ. Interleukin-12 (IL-12) administration into mice induced strong cytotoxicities of NK cell-depleted liver and lung mononuclear cells (MNC) comparable to those without NK-cell depletion and inhibited metastases in either organ. In contrast, in both NK cell- and NK1+ int T-cell-depleted mice, IL-12 could not induce cytotoxic activity of liver and lung MNC and metastases in both organs increased with or without IL-12 treatment. These results confirmed the fact that NK+ int T cells are more potent antitumour effectors than NK cells against experimental haematogenous tumour metastases.

Animals↗
PubMed1997

Contribution of Fas ligand to T cell-mediated hepatic injury in mice.

BACKGROUND & AIMS: Fas has been implicated in liver damage. The aim of this study was to investigate the role of its ligand to induce hepatocyte death and liver damage in T cell-dependent hepatitis. METHODS: Fas ligand-mediated lysis of primary hepatocytes from C57BL/6 wild-type, Fas ligand-deficient gld, and Fas-deficient lpr mice and concanavalin A-induced hepatitis in these mice were assessed. RESULTS: Freshly isolated hepatocytes from wild-type or gld mice, but not those from lpr mice, were susceptible to Fas ligand-mediated lysis. When concanavalin A was intravenously administered into wild-type mice, they developed acute hepatic injury with massive degenerative changes in hepatocytes. In contrast, both gld and lpr mice had lower aminotransferase levels with milder histological changes. Reverse-transcription polymerase chain reaction and flow cytometric analysis showed that Fas ligand was induced in the liver shortly after the concanavalin A injection and was predominantly expressed on intrahepatic T cells. Administration of monoclonal antibody neutralizing mouse Fas ligand could reduce the aminotransferase increase. CONCLUSIONS: The results indicate that Fas ligand plays a role in the T cell-dependent hepatitis induced by concanavalin A administration.

Alanine Transaminase↗
PubMed1997

Sudden death in chronic dialysis patients.

METHODS: Causes of sudden death were investigated in 113 chronic dialysis patients who died during the 10-year period from July 1979 to January 1989; postmortem examination was performed on 93 of the cases (autopsy rate; 82.3%). Sudden death was regarded as death 24 h after the onset of acute illness in patients without any restriction in their daily activities. There were 35 sudden death cases out of the 93 autopsied chronic dialysis patients. We analysed the causes of sudden death for all chronic dialysis patients and for those who died suddenly. RESULTS: The mean age of the 93 cases was 61.4 +/- 10.5 years (+/-SD). Stroke was the most frequent cause of death (24 cases, 25.8%) in the 93 autopsied cases. This was followed by cardiac disease in 18 (19.4%), infectious disease in 16 (17.2%), malignancy in 14 (15.1%), and dissecting aortic aneurysm in 5 (5.4%). The mean age of the 35 sudden death cases was 60.9 +/- 10.9 years. Of the 35 sudden death cases in chronic dialysis patients, dissecting aortic aneurysm was the most common cause of sudden death (5 cases, 14.3%), followed by cerebral haemorrhage in three (8.6%), acute subdural haematoma in three (8.6%), acute myocardial infarction in two (5.7%), cerebral infarction in two (5.7%), and subarachnoidal haemorrhage in one (2.9%). CONCLUSIONS: Dissecting aortic aneurysm, leading frequently to stroke as a cause of sudden death in chronic dialysis patients, at least in Japan, should be carefully differentiated from other cardiac diseases in chronic dialysis patients, such as severe atherosclerosis.

Adult↗
PubMed1997

Purification and characterization of wall-bound exo-1,3-beta-D-glucanase from barley (Hordeum vulgare L.) seedlings.

A beta-D-glucanase activity hydrolyzing 1,3:1,4-beta-D-glucan was released from the cell walls of barley by 3 M LiCl treatment. It was purified by sequential cation-exchange, gel-filtration and hydrophobic chromatography. The molecular mass of the glucanase was 66 kDa as determined by SDS-polyacrylamide gel electrophoresis. Sequence determination of the first thirty amino acids of the N-terminus revealed a high homology of this enzyme to the Pseudomonas 1,4-beta-D-glucosidase (56.5%). The purified beta-D-glucanase has a pH optimum at 5.0, and hydrolyzes oligosaccharides containing beta-D-1,3 or beta-D-1,4 linkage. The glucanase showed maximum hydrolytic activity toward laminaritetraose, the rate being about two times that of cellotetraose and about four times that of gentiobiose. Polysaccharides such as lichenan, 1,3:1,4-beta-D-glucan (from barley), laminarin and pustulan are also hydrolyzed, but not carboxylmethyl-curdlan, carboxymethyl-cellulose, xyloglucan and maltose. The purified beta-D-glucanase yielded monomeric glucose from laminarihexaose, and exhibited characteristics of an exo-1,3-beta-D-glucanase (EC 3.2.1.58). The activity and biochemical characteristics of this enzyme suggest that it is an exo-1,3-beta-D-glucanase involved in the rapid turnover of 1,3:1,4-beta-D-glucan in barley cell walls during seedling growth.

Amino Acid Sequence↗