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1.
A new lectin has been purified to homogeneity from the phloem exudate of snake gourd (Trichosanthes anguina) by affinity chromatography on chitin. The snake gourd phloem lectin (SGPL) specifically binds chitooligosaccharides and their inhibitory potency increased with increase in size. PAGE and SDS-PAGE studies indicate that SGPL is a heterodimer, in which the two subunits (48 and 53 kDa) are joined by disulfide bonds. Consistent with this, electrospray-ionization mass spectrum yielded the exact mass of the protein as 104,621.8 Daltons. CD studies showed that SGPL contains about 9% α-helix, 39% β-sheet, 20% β-turns and 32% unordered structures and that saccharide binding does not significantly affect its secondary and tertiary structures. Titration calorimetric studies indicate that the dimeric lectin binds two ligand molecules [(GlcNAc)3–6] with association constants determined at 25 °C being 1.7 × 105 and 3.6 × 105 M−1, for chitotriose and chitohexaose, respectively. Binding of all the chitooligosaccharides is governed by enthalpic forces, whereas the contribution from binding entropies was unfavorable. These results suggest that the SGPL-saccharide interaction is stabilized by hydrogen bonding and van der Waals’ interactions. Enthalpy–entropy compensation was observed for the SGPL-chitooligosaccharide interaction, suggesting that water molecules play a key role in the binding process. 相似文献
2.
Physicochemical and saccharide-binding studies have been performed on Trichosanthes cucumerina seed lectin (TCSL). The agglutination activity of TCSL is highest in the pH range 8.0-11.0, whereas below pH 7.0 it decreases quite rapidly, which is consistent with the involvement of imidazole side chains of His residues, which titrate in this pH range, in the sugar-binding activity of the lectin. The lectin activity is unaffected between 0 and 60 degrees C, but a sharp decline occurs at higher temperatures. Isoelectric focusing studies show that TCSL has three isoforms with pI values of 5.3, 6.2, and 7.1, with the isoform of pI 6.2 being the most abundant. Circular dichroism spectroscopic studies reveal that TCSL contains about 28.4% beta-sheet, 10.6% beta-turns, 7% polyproline type 2 structure, with the remainder comprising unordered structure; the alpha-helix content is negligible. Binding of 4-methylumbelliferyl-beta-D-galactopyranoside (MeUmbbetaGal) to TCSL results in a significant increase in the fluorescence intensity of the ligand, and this change has been used to obtain the association constant for the interaction. At 25 degrees C, the association constant, K(a), for the TCSL-MeUmbbetaGal interaction was determined as 6.9 x 10(4)M(-1). Binding of nonfluorescent, inhibitory sugars was studied by monitoring their ability to reverse the fluorescence changes observed when MeUmbbetaGal was titrated with TCSL. 相似文献
3.
Konozy EH Bernardes ES Rosa C Faca V Greene LJ Ward RJ 《Archives of biochemistry and biophysics》2003,410(2):222-229
A lectin was isolated from the saline extract of Erythrina speciosa seeds by affinity chromatography on lactose-Sepharose. The lectin content was about 265 mg/100g dry flour. E. speciosa seed lectin (EspecL) agglutinated all human RBC types, showing no human blood group specificity; however a slight preference toward the O blood group was evident. The lectin also agglutinated rabbit, sheep, and mouse blood cells and showed no effect on horse erythrocytes. Lactose was the most potent inhibitor of EspecL hemagglutinating activity (minimal inhibitory concentration (MIC)=0.25 mM) followed by N-acetyllactosamine, MIC=0.5mM, and then p-nitrophenyl alpha-galactopyranoside, MIC=2 mM. The lectin was a glycoprotein with a neutral carbohydrate content of 5.5% and had two pI values of 5.8 and 6.1 and E(1%)(1 cm) of 14.5. The native molecular mass of the lectin detected by hydrodynamic light scattering was 58 kDa and when examined by mass spectroscopy and SDS-PAGE it was found to be composed of two identical subunits of molecular mass of 27.6 kDa. The amino acid composition of the lectin revealed that it was rich in acidic and hydroxyl amino acids, contained a lesser amount of methionine, and totally lacked cysteine. The N-terminal of the lectin shared major similarities with other reported Erythrina lectins. The lectin was a metaloprotein that needed both Ca(2+) and Mn(2+) ions for its activity. Removal of these metals by EDTA rendered the lectin inactive whereas their addition restored the activity. EspecL was acidic pH sensitive and totally lost its activity when incubated with all pH values between pH 3 and pH 6. Above pH 6 and to pH 9.6 there was no effect on the lectin activity. At 65 degrees C for more than 90 min the lectin was fairly stable; however, when heated at 70 degrees C for 10 min it lost more than 80% of its original activity and was totally inactivated at 80 degrees C for less than 10 min. Fluorescence studies of EspecL indicated that tryptophan residues were present in a highly hydrophobic environment, and binding of lactose to EspecL neither quenched tryptophan fluorescence nor altered lambda(max) position. Treating purified EspecL with NBS an affinity-modifying reagent specific for tryptophan totally inactivated the lectin with total modification of three tryptophan residues. Of these residues only the third modified residue seemed to play a crucial role in the lectin activity. Addition of lactose to the assay medium did not provide protection against NBS modification which indicated that tryptophan might not be directly involved in the binding of haptenic sugar D-galactose. Modification of tyrosine with N-acetylimidazole led to a 50% drop in EspecL activity with concomitant acetylation of six tyrosine residues. The secondary structure of EspecL as studied by circular dichroism was found to be a typical beta-pleated-sheet structure which is comparable to the CD structure of Erythrina corallodendron lectin. Binding of lactose did not alter the EspecL secondary structure as revealed by CD examination. 相似文献
4.
Purification and partial characterization of a lectin from the seeds of Trichosanthes kirilowii Maximowicz 总被引:2,自引:0,他引:2
A I Falasca A Abbondanza L Barbieri A Bolognesi C A Rossi F Stirpe 《FEBS letters》1989,246(1-2):159-162
A lectin was purified from the seeds of Trichosanthes kirilowii, belonging to the family Cucurbitaceae, growing in China. The lectin is a glycoprotein of 57 kDa, consists of two subunits with apparent molecular masses of 37 and 25 kDa, is specific for galactose, and is not mitogenic for human lymphocytes. 相似文献
5.
AgaXa is a thermostable β-agarase from the agar-degrading bacterium Catenovulum sp. X3. To further understand the mechanism of protein stabilization of AgaXa, several mutants were generated by random and site-directed mutagenesis, and they were subsequently screened by analysing their enzymatic activity and thermostability. Four mutants (V197D, P259H, C442S and C528S) were found for which the enzyme activity and thermostability were significantly decreased. Moreover, secondary structures determined by circular dichroism (CD) showed that mutants V197D and P259H presented a higher percentage of α-helix but fewer β-strands than wild-type (WT) AgaXa. On the contrary, no significant changes were observed in the secondary structures of mutants C442S and C528S. Through the treatment by proteinase K, different digested profiles were generated from mutants V197D and P259H when compared to WT, and mutants C442S and C528S was observed with more digested protein fragments. These results indicate that the enzymatic activity and stability of AgaXa is mainly related to its hydrophobic structure and disulphide bonds. Furthermore, carbohydrate-binding ability was also analysed for the mutants of N- and C-terminal deletions, and the results showed that agarose binding capability was not changed, indicating that the carbohydrate-binding module is probably located in the middle of the β-agarase AgaXa. 相似文献
6.
A galactose-specific lectin has earlier been isolated from the seeds of Dolichos lablab in our laboratory by conventional protein purification methods. We now established conditions to bind the lectin on Sepharose-galactose gel in the presence of 1.5 M ammonium sulfate in Tris-buffered saline, pH 7.4. It can be specifically eluted with 0.3 M galactose. The purified lectin is a glycoprotein, binds to Con A, agglutinates erythrocytes, and has an apparent native molecular weight of 120 +/- 5 kDa. In SDS-PAGE under reducing conditions, it dissociates into two subunits of molecular mass (Mr) 31 and 29 kDa. Among a number of sugars tested for inhibitory activity of the lectin, galactose was found to be a potent inhibitor. Rabbit polyclonal antibody to the purified lectin specifically reacted with the lectin subunits in Western blot analysis and additionally, an antibody raised to the isolated 31 kDa subunit show reactivity with both the subunits. Amino terminal sequences of both the subunits are identical. The purified lectin is stable up to 40 degrees C with a pH optimum of 7.4. The lectin has a high content of acidic amino acids and lacks sulfur-containing amino acids. Chemical modification of the lectin with group-specific reagents indicates the possible role of histidine, lysine, and tyrosine residues in lectin activity. 相似文献
7.
Aaron Kerman Vettai S. Ananthanarayanan 《Biochimica et Biophysica Acta - Proteins and Proteomics》2005,1747(1):133-140
We report here a procedure for the production in Escherichia coli and subsequent purification and characterization of an 80-residue fragment of the human μ-opioid receptor. The fragment (‘TM2–3’), which comprises the second and third transmembrane segments as well as the first extracellular loop of the receptor, was expressed as a fusion with glutathione-S-transferase. The fusion protein, which accumulated in insoluble inclusion bodies, was solubilized with N-lauroylsarcosine, and TM2–3 was obtained by thrombin cleavage of the fusion protein followed by reversed-phase HPLC purification. CD spectroscopy of TM2–3 in lysophosphatidylcholine micelles showed that TM2–3 adopts ~50% α-helical structure in this environment, with the remainder consisting of disordered and/or β-structure. This is consistent with the assumption of an α-helical structure by the two membrane-spanning regions and a nonhelical structure in the loop region of TM2–3. Fluorescence spectroscopy and fluorescence quenching experiments suggested that the extracellular loop lies near the surface of the lysophosphatidylcholine micelle. Our work shows that the study of large receptor fragments is a technically accessible approach to the study of the structural properties of the μ-opioid receptor and, possibly, other G-protein-coupled receptors as well. 相似文献
8.
FN Pereira-Junior HC Silva BT Freitas BA Rocha KS Nascimento CS Nagano RB Leal AH Sampaio BS Cavada 《Journal of molecular recognition : JMR》2012,25(8):443-449
Platymiscium floribundum lectin (PFL), a mannose/N-acetyl-D-glucosamine-specific lectin, was isolated from P. floribundum seeds using Sepharose-mannose affinity media chromatography. PFL is a glycoprotein that is a potent agglutinin for rabbit erythrocytes. In addition, PFL is highly stable because it is able to maintain its hemagglutinating activity after exposure to temperatures of up to 60 °C for 1 h and exposure to a wide pH range. The PFL purification process was monitored using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the results showed that the purified lectin consists of a single band with a molecular mass of approximately 29 kDa in either the presence or the absence of a reducing agent. The analysis of purified PFL by electrospray ionization-mass spectrometry showed that most ions had a molecular weight of 27,053 ± 2 Da, and other less abundant ions had similar molecular weights. Gel filtration shows that the lectin exists as a dimer in solution with mass at approximately 65 kDa. Sixteen peptides were sequenced, and as a result, a total of 130 amino acids were identified and resulted in a coverage of approximately 65% of the PFL sequence. The partial sequence of PFL was aligned with sequences of other lectins from evolutionarily related species, and PFL showed considerable similarity to the other lectins. 相似文献
9.
A plant lectin was isolated from barley (Hordeum vulgare) coleoptiles using acidic extraction and different chromatographic methods. Sequencing of more than 50% of the protein sequence
by Edman degradation confirmed a full-length cDNA clone. The subsequently identified open reading frame encodes for a 15 kDa
protein which could be found in the soluble fraction of barley coleoptiles. This protein exhibited specificity towards mannose
sugar and is therefore, accordingly named as Horcolin (Hordeum vulgare coleoptile lectin). Database searches performed with
the Horcolin protein sequence revealed a sequence and structure homology to the lectin family of jacalin-related lectins.
Together with its affinity towards mannose, Horcolin is now identified as a new member of the mannose specific subgroup of
jacalin-related lectins in monocot species. Horcolin shares a high amino acid homology to the highly light-inducible protein
HL#2 and, in addition to two methyl jasmonic acid-inducible proteins of 32.6 and 32.7 kDa where the jasmonic acid-inducible
proteins are examples of bitopic chimerolectins containing a dirigent and jacalin-related domain. Immunoblot analysis with
a cross-reactive anti-HL#2 antibody in combination with Northern blot analysis of the Horcolin cDNA revealed tissue specific
expression of Horcolin in the coleoptiles. The function of Horcolin is discussed in the context of its particular expression
in coleoptiles and is then compared to other lectins, which apparently share a related response to biotic or abiotic stress
factors. 相似文献
10.
Alfa U. Bari Helton C. Silva Mayara T. L. Silva Francisco N. Pereira Júnior João B. Cajazeiras Alexandre H. Sampaio Rodrigo B. Leal Edson H. Teixeira Bruno A. M. Rocha Kyria S. Nascimento Celso S. Nagano Benildo S. Cavada 《Journal of molecular recognition : JMR》2013,26(8):351-356
A new mannose/glucose‐specific lectin, named DigL, was purified from seeds of Dialium guineense by a single step using a Sepharose 4b‐Mannose affinity chromatography column. DigL strongly agglutinated rabbit erythrocytes and was inhibited by d ‐mannose, d ‐glucose, and derived sugars, especially α‐methyl‐d ‐mannopyranoside and N‐acetyl‐d ‐glucosamine. DigL has been shown to be a stable protein, maintaining its hemagglutinating activity after incubation at a wide range of temperature and pH values and after incubation with EDTA. DigL is a glycoprotein composite by approximately 2.9% of carbohydrates by weight. By sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis, the purified DigL exhibited an electrophoretic profile consisting of a broad band of 28–30 kDa. Analysis using electrospray ionization mass spectrometry indicated that purified DigL possesses a molecular average mass of 28 452 ± 2 Da and shows the presence of possible glycoforms. In addition, DigL exhibited an intermediary toxic effect on Artemia sp. nauplii, and this effect was both dependent on native structure and mediated by a carbohydrate‐binding site. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
11.
Purification and molecular characterization of a novel mannose‐specific lectin from Dioclea reflexa hook seeds with inflammatory activity
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Vanir R. Pinto‐Junior Jorge L. A. Correia Ronniery I. Pereira Francisco N. Pereira‐Junior Mayara Q. Santiago Vinicius J. S. Osterne Juliana C. Madeira João B. Cajazeiras Celso S. Nagano Plinio Delatorre Ana M. S. Assreuy Kyria S. Nascimento Benildo S. Cavada 《Journal of molecular recognition : JMR》2016,29(4):134-141
A novel lectin present in Dioclea reflexa seeds (DrfL) was discovered and described in this study. DrfL was purified in a single step by affinity chromatography in a Sephadex G‐50 column. The lectin strongly agglutinated rabbit erythrocytes and was inhibited by α‐methyl‐d ‐mannoside, d ‐mannose, and d ‐glucose. The hemagglutinating activity of DrfL is optimum at pH 5.0–7.0, stable up to 50 °C, and dependent on divalent cations. Similar to other lectins of the subtribe Diocleinae, the analysis by mass spectrometry indicated that DrfL has three chains (α, β, and γ) with masses of 25 562, 12 874, and 12 706 Da, respectively, with no disulfide bonds or glycosylation. DrfL showed inflammatory activity in the paw edema model and exhibited low cytotoxicity against Artemia sp. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
Lacquer polysaccharide (LP) was isolated from the sap of lac tree (Rhus vernicifera). Its derivatives, carboxymethyl LP, sulfated LP and debranching LP were prepared. Their structure was analyzed by GPC, FT-IR and NMR spectroscopy. The sugar components of carboxymethyl and sulfated LPs hardly changed, but the molecular weight of the former decreased. The side chains of LPs were partially removed using sodium periodate in mild conditions and the pyranose ring β-configuration of products obtained was not changed. Bioactivity of natural and modified LPs against leukopenia induced by cyclophosphamide (CP) was investigated in mice. LP exhibited a significant bioactivity (P<0.05) compared to positive control group (CP). The bioactivity could increase slightly with the increasing of the contents of carboxymethyl groups. However, with the removal of the side chains and the incorporation of sulfate groups, the bioactivity gradually decreased. These showed that the bioactivity of lacquer polysaccharides against leukopenia induced by CP was strongly dependent on the types of ionic groups of the polysaccharides and concerned with the side chains with 4-O-methyl-β-glucuronic acid in the terminal. 相似文献
13.
Pérez Gerardo 《Phytochemistry》1984,23(6):1229-1232
A galactose-specific lectin was isolated from the seeds of Erythrina edulis. The protein was purified by affinity chromatography of the globulin fraction on an allyl-galactoside polyacrylamide gel. The hemagglutination properties, amino acid composition, A280, MW of the protein and of its subunits, carbohydrate content, electrophoretic pattern and isoelectric point were determined. Comparison of its properties with those of other Erythrina lectins shows that the protein is a distinct member of this group of lectins. 相似文献
14.
P Casellas D Dussossoy A I Falasca L Barbieri J C Guillemot P Ferrara A Bolognesi P Cenini F Stirpe 《European journal of biochemistry》1988,176(3):581-588
A protein, here named trichokirin, was extracted from the seeds of Trichosanthes kirilowii and purified by ion-exchange and gel-filtration chromatography. Trichokirin is a basic glycoprotein of apparent relative molecular mass of 27,000 with a strong ribosome-inactivating activity. Alignment of the trichokirin, trichosanthin and momordin N-terminal sequences shows a substantial degree of homology. Trichokirin was conjugated to a monoclonal antibody directed against the Thy 1.2 antigen with the cleavable dimethyl 3,3'-dithiobispropionimidate cross-linking reagent. This immunotoxin selectively killed leukemia cells expressing the Thy 1.2 antigen. The addition of ammonium chloride, which increases the cytotoxicity of ricin A-chain immunotoxins, blocks that of the trichokirin immunotoxin, suggesting that they enter cells by different mechanisms. In vivo studies showed that the pharmacokinetic properties of the trichokirin immunotoxin could be more advantageous than those of the ricin A-chain immunotoxins for in vivo applications. 相似文献
15.
Summary Circular dichroism spectroscopy was used to study the conformational change of a peptide containing a CD4 binding region of HIV-1 envelope glycoprotein gp120 complexed with a CD4 fragment. In free solution the gp120 peptide exists primarily as -sheet and random coil. Upon association with the peptide, encompassing a critical gp120 binding site on the extracellular domain 1 of CD4, the -helical content of the complex relative to that of the two component peptides increases significantly, at the expense of random coil and turn. An increase in the helix structure for the gp120 peptide, but not the CD4 peptide, was observed in 30% trifluoroethanol (TFE)/H2O (v:v) solution. The conformational change in the gp120 C4 peptide when complexing with CD4 is proposed as part of the process that facilitates the membrane fusion between the virion and its target cell.Abbreviations CD
circular dichroism
- HIV
human immunodeficiency virus
- AIDS
acquired immunodeficiency syndrome
- Fmoc
9-fluorenylmethoxycarbonyl
- mAb
monoclonal antibody
- gp
glycoprotein
- TFE
trifluoroethanol
- HPLC
high-performance liquid chromatography 相似文献
16.
A lectin was isolated and purified from the culture filtrate of the plant pathogenic fungus Macrophomina phaseolina by a combination of ammonium sulfate precipitation, affinity chromatography on fetuin-Sepharose 4B and ion-exchange chromatography on DEAE-A 50. The lectin designated MPL was homogeneous by PAGE and HPLC and a monomeric protein with a molecular weight of approximately 34 kDa as demonstrated by SDS-PAGE. It is a glycoprotein and agglutinated human erythrocytes regardless of the human blood type. Neuraminidase treatment of erythrocytes reduced the agglutination activity of the lectin. It is thermally stable and exhibits maximum activity between pH 6 and 7.2. Its carbohydrate binding specificity was investigated both by hapten inhibition of hemagglutination and by enzyme-conjugated lectin inhibition assay. Although, M. phaseolina lectin bound sialic acid, it exhibited binding affinity towards neuraminyl oligosaccharides of N-linked glycoproteins, alpha-Neu5Ac-(2-->3)-beta-Gal-(1-->4)-GlcNAc being maximum. 相似文献
17.
Purification and characterization of a mannose-binding lectin from the rhizomes of Aspidistra elatior Blume with antiproliferative activity 总被引:1,自引:0,他引:1
Xu X Wu C Liu C Luo Y Li J Zhao X Damme EV Bao J 《Acta biochimica et biophysica Sinica》2007,39(7):507-519
A lectin with a novel N-terminal amino acid sequence was purified from the rhizomes of Aspidistra elatior Blume by ammonium sulphate precipitation, ion exchange chromatography on diethylaminoethyl-Sepharose and carboxymethyl-Sepharose and gel filtration chromatography on Sephacryl S-100. The A. elatior Blume lectin (AEL) is a heterotetramer with a molecular mass of 56 kDa and composed of two homodimers consisting of two different polypeptides of 13.5 kDa and 14.5 kDa held together by noncovalent interactions. Hapten inhibition assay indicated that hemagglutinating activity of AEL towards rabbit erythrocytes could be inhibited by D-mannose, mannan, thyroglobulin and ovomucoid. The lectin was stable up to 70 ℃ , and showed maximum activity in a narrow pH range of 7.0-8.0. Chemical modification and spectrum analysis indicated that tryptophan, arginine, cysteine and carboxyl group residues were essential for its hemagglutinating activity. However, they might not be present in the active center, except some carboxyl group residues. AEL also showed significant in vitro antiproliferative activity towards Bre-04 (66%), Lu-04 (60%) and HepG2 (56%) of human cancer cell lines. 相似文献
18.
Jong Won Han Min Gui Jung Min Jung Kim Kang Sup Yoon Key Pyoung Lee Gwang Hoon Kim 《Phycological Research》2010,58(2):143-150
A d ‐mannose specific lectin was purified from the green marine alga, Bryopsis plumosa (Huds.) Ag. The lectin agglutinated horse and sheep erythrocytes. Matrix assisted laser desorption/ionization time of flight mass spectrometry, size exclusion chromatography, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) and two dimensional gel electrophoresis (2DE) results showed that the lectin was a monomer with molecular weight of 17 kDa and pI 7.3. The agglutinating activity was inhibited by d ‐mannose (1 mM), α‐methyl‐D‐mannose (4 mM) and l ‐fucose (8 mM). d ‐glucose (125 mM) showed weak inhibition. The lectin did not need divalent cations for agglutinating activity. N‐terminal amino acid sequence of the lectin was analyzed. As the lectin was novel, we named it BPL‐2 (Bryopsis plumosa lectin 2). Full cDNA sequence of BPL‐2 was obtained using cDNA library. It was comprised of 624 bp of open reading frame and 167 bp/57 bp of 3′/5′ untranslated regions as well as N‐terminal signal peptide. No antimicrobial activity of BPL‐2 was observed in four bacteria strains tested. 相似文献
19.
“Juemingzi”, a source of traditional Chinese herbal medicine, has been demonstrated to play a role in decreasing serum cholesterol
concentration. In this study, a novel protein, which has shown an inhibitory effect on cholesterol biosynthesis, was isolated
from Senna obtusifolia L. seed by gel filtration and ion exchange chromatography. The novel protein’s molecular mass was 19.7 kD and its pI was
4.80. Both SDS-PAGE and isoelectric-focusing (IEF) revealed a single Coomassie brilliant blue stained band, indicating that
the novel protein was a single peptide. The N-terminal amino acid sequence of the protein was IPYISASFPLNIEFLPSE, which had
no similarity with any other protein sequences in the NCBI protein database. Circular dichroism (CD) signals indicated that
S. obtusifolia seed protein contained 12.5% α-helix, 55.6% β-sheet, and 31.9% random coil
Supported by Guangdong Provincial Department of Science and Technology (Grant No. 2003C34409) and Guangzhou Civil Department
of Science and Technology (Grant No. 2002Z3-85041) 相似文献
20.
Donald L. Silhacek Stephen G. Miller Curtis L. Murphy 《Archives of insect biochemistry and physiology》1994,25(1):55-72
The 85K storage protein that accumulates in the hemolymph of Galleria mellonella during the final larval instar was isolated and purified from newly molted pupae. The separation of fresh hemolymph proteins from larvae or pupae by different chromatographic and electrophoretic procedures indicated the native protein had a Mr of 170,000 and consisted of two identical 85K subunits. Crosslinking experiments using fresh hemolymph followed by Western blotting also indicated a dimeric structure for the native protein. Analyses of the dimer purified from pupal hemolymph indicated that 85K was a glycoprotein, containing approximately 6.5% neutral sugar and about 1.9% amino sugar. Like other insect flavin-binding proteins, 85K has a relatively high histidine content but an uncharacteristically high arginine content. The purified 85K dimer did not bind riboflavin, suggesting that the integrity of the molecule had been altered during purification. However, 85K purified in low yield by Affi-Gel Blue chromatography, did bind riboflavin, indicating that under certain, undefined conditions the functional integrity of the protein could be retained during purification. © 1994 Wiley-Liss, Inc. 1 This article is a US Government work and, as such, is in the public domain in the United States of America. 相似文献