Purification and Product Characterization of Lipoxygenase from Opium Poppy Cultures (Papaver somniferum L.).

Opium poppy (Papaver somniferum L.) is an ancient medicinal plant producing pharmaceutically important benzylisoquinoline alkaloids. In the present work we focused on the study of enzyme lipoxygenase (LOX, EC 1.13.11.12) from opium poppy cultures. LOX is involved in lipid peroxidation and lipoxygenase oxidation products of polyunsaturated fatty acids have a significant role in regulation of growth, development and plant defense responses to biotic or abiotic stress. The purpose of this study was to isolate and characterize LOX enzyme from opium poppy callus cultures. LOX was purified by ammonium sulfate precipitation and then followed by hydrophobic chromatography using Phenyl-Sepharose CL-4B and hydroxyapatite chromatography using HA Ultrogel sorbent. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis and immunoblotting revealed that LOX from opium poppy cultures was a single monomeric protein showing the relative molecular weight of 83 kDa. To investigate the positional specificity of the LOX reaction, purified LOX was incubated with linoleic acid and the products were analyzed by high-performance liquid chromatography in two steps, firstly with reverse phase (120-5 Nucleosil C18 column) and secondly with normal phase (Zorbax Rx-SIL column). LOX converted linoleic acid primarily to 13-hydroperoxy-(9Z,11E)-octadecadienoic acids (78%) and to a lesser extent 9-hydroperoxy-(10E,12Z)-octadecadienoic acids (22%). Characterization of LOX from opium poppy cultures provided valuable information in understanding LOX involvement in regulation of signaling pathways leading to biosynthesis of secondary metabolites with significant biological activity.

Antitumor bioactivity of porphyran extracted from Pyropia yezoensis Chonsoo2 on human cancer cell lines.

BACKGROUND: Pyropia yezoensis, rich in porphyran, is a medicine-edible red alga. In the present study, the physicochemical characteristics, conformational states and antitumor activities of a novel porphyran extracted from the high-yield algal strain Pyropia yezoensis Chonsoo2 and its two degraded derivatives by gamma irradiation were investigated. RESULTS: Pyropia yezoensis porphyran is a water-soluble, triple-helical sulfated hetero-galactopyranose, named PYP. PYP was degraded by gamma irradiation at 20 kGy and 50 kGy, giving two low molecular weight derivatives comprising PYP-20 and PYP-50, respectively. PYP with a higher molecular weight has a solution conformation different from PYP-20 and PYP-50. Three porphyrans had no toxicity in normal human liver cells (HL-7702) and showed antitumor effects on Hep3B, HeLa and MDA-MB-231. They had better antitumor against HeLa cells, exhibiting a similar inhibition ratio compared to 5-fluorouracil, with PYP especially exhibiting a higher inhibition ratio than 5-fluorouracil. With respect to HeLa cells, the different antitumor activities might be related to porphyran molecular weight and solution conformation. Furthermore, the HeLa cell cycle was blocked in the G2/M phase after PYP treatment, leading to cell proliferation inhibition. The induction of cell cycle arrest was related to the changes in the expression of p21, p53, Cyclin B1 and cyclin-dependent kinase 1. CONCLUSION: Pyropia yezoensis porphyran, as applied to medicine and functional food, could potentially be used as a non-toxic natural adjuvant in cancer therapy. © 2019 Society of Chemical Industry.

Structure and Bioactivities of Porphyrans and Oligoporphyrans.

BACKGROUND: Pyropia (Porphyra), commonly known as nori or laver, is an important food source in many parts of the world. Edible dried Pyropia contains numerous nutrients and biofunctional components, including proteins, vitamins, eicosapentaenoic acid, minerals, carotenoids, mycosporine-like amino acids, and carbohydrate, and one of the compounds which we are interested in is porphyran, a sulfated polysaccharide comprising the hot-water-soluble portion of Pyropia cell walls. Researchers have performed a large number of in-depth studies on the biological activity and potential therapeutic applications of porphyrans and oligoporphyrans. METHODS: This mini review aims to provide comprehensive and update overview on the source, extraction, structure, biological activities and structure-activity relationships of porphyrans and oligoporphyrans based on the studies in the past 30 years which were included in Web of Science. RESULTS: The structure of porphyran has been basically determined given that its straight chain is relatively simple, and the skeleton structure has been described. The extraction methods were simplified continuously, but different extraction methods and post- processing methods still had great influence on the structure and composition of porphyran, so there was no standardized extraction process which can achieve quality control until now. In order to obtain oligoporphyrans, there are a variety of degradation methods, including chemical method, physical method and enzymatic method, but it is worth mentioning that specific degradation enzyme is still unavailable. Studies on the biological and pharmacology properties include antioxidant, anti-tumor, anti-inflammatory, immunomodulation, anti-cardiovascular and cerebrovascular diseases and drug delivery. CONCLUSION: Owing to the therapeutic potential and drug delivery applications, porphyran and oligoporphyrans are expected to be further developed as a medicine against human diseases, as well as a supplement in cosmetics and health products.

Downstream processing of a plant-derived malaria transmission-blocking vaccine candidate.

Plants as a platform for recombinant protein expression are now economically comparable to well-established systems, such as microbes and mammalian cells, thanks to advantages such as scalability and product safety. However, downstream processing accounts for the majority of the final product costs because plant extracts contain large quantities of host cell proteins (HCPs) that must be removed using elaborate purification strategies. Heat precipitation in planta (blanching) can remove ∼80% of HCPs and thus simplify further purification steps, but this is only possible if the target protein is thermostable. Here we describe a combination of blanching and chromatography to purify the thermostable transmission-blocking malaria vaccine candidate FQS, which was transiently expressed in Nicotiana benthamiana leaves. If the blanching temperature exceeded a critical threshold of ∼75 °C, FQS was no longer recognized by the malaria transmission-blocking monoclonal antibody 4B7. A design-of-experiments approach revealed that reducing the blanching temperature from 80 °C to 70 °C restored antibody binding while still precipitating most HCPs. We also found that blanching inhibited the degradation of FQS in plant extracts, probably due to the thermal inactivation of proteases. We screened hydrophobic interaction chromatography materials using miniature columns and a liquid-handling station. Octyl Sepharose achieved the highest FQS purity during the primary capture step and led to a final purity of ∼72% with 60% recovery via step elution. We found that 30-75% FQS was lost during ultrafiltration/diafiltration, giving a final yield of 9 mg kg-1 plant material after purification based on an initial yield of ∼49 mg kg-1 biomass after blanching.

Increase in anti-inflammatory activities of radical-degraded porphyrans isolated from discolored nori (Pyropia yezoensis).

The anti-inflammatory properties of porphyrans (D1-D4) obtained from four discolored nori (Pyropia yezoensis) with different growth backgrounds were studied to examine possible variations in their bioactivities. Elution profiles of the porphyrans on Sepharose 4B indicated that D2-porphyran had relatively lower-molecular-size porphyrans than the other porphyrans. Inhibitory activities of the four porphyrans against nitric oxide (NO) and tumor necrosis factor-α (TNF-α) secretion by lipopolysaccharide (LPS)-stimulated RAW264.7 cells were different, whereas no significant differences were observed in the sulfate and anhydrogalactose levels. D2-porphyran showed the highest inhibitory activity against NO and TNF-α secretion by LPS-stimulated RAW264.7 cells, whereas D3- and D4-porphyrans had almost no activity. All porphyrans were efficiently degraded by free radical generated with ascorbate and hydrogen peroxide. The free-radical degradation resulted in a significant increase in the inhibitory activities of the four porphyrans against NO and TNF-α secretion, with varying rates depending on the porphyrans. The ability of D2-porphyran to suppress the receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells was also significantly enhanced after degradation. Our results suggest that molecular size is an important factor affecting the anti-inflammatory activity of porphyrans, and radical degradation might be a promising procedure to obtain active low-molecular-size porphyrans.

Inhibitory effect of sulphated polysaccharide porphyran (isolated from Porphyra yezoensis) on RANKL-induced differentiation of RAW264.7 cells into osteoclasts.

Safe and efficient therapeutic agents for bone diseases are required in natural sources. We previously found that edible seaweed-derived polysaccharide porphyran exhibited anti-inflammatory effects through the down regulation of nuclear factor-κB. The aim of this study was to investigate the availability of porphyran as a therapeutic agent for bone diseases. The effects of porphyran on receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis in RAW264.7 cells were examined. Porphyran suppressed RANKL-induced osteoclast formation in a concentration-dependent manner (6.25-50 µg/ml) without any cytotoxic effects. Furthermore, real-time polymerase chain reaction analyses indicated that porphyran at 50 µg/ml significantly attenuated the RANKL-induced increase in the mRNA levels of osteoclastogenesis-related marker genes such as nuclear factor of activated T cells, tartrate-resistant acid phosphatase, cathepsin K, and matrix metalloproteinase-9 in RAW264.7 cells. To our knowledge, this is the first report showing that edible-seaweed-derived polysaccharide porphyran can suppress RANKL-induced osteoclastogenesis. Our results suggest that porphyran can be used as a safe therapeutic agent to improve osteoclast-related pathological conditions.

In vivo antihyperlipidemic and antioxidant activity of porphyran in hyperlipidemic mice.

The hypolipidemic and antioxidant effects of porphyran from the red algae Porphyra haitanensis as a dietary supplement were evaluated in mice. The levels of serum TC, TG and LDL-C in MP group increased significantly (p<0.05 or p<0.01) by 28.5%, 29.4% and 33.5% compared with the model group. These significant rises were accompanied by significant declines of plasma HDL-C by 21.6% compared with the model group. In addition, the liver content of malondialdehyde significantly decreased, while the superoxide dismutase, catalase, glutathione peroxidase activities significantly increased. The levels of serum SOD and GSH-Px in MP group increased significantly by 51.2% and 99.6% compared with the model group. The results suggested that porphyran could be used as functional foods and natural drugs in preventing the hyperlipidemia and this activity might be attributed to its antioxidant potential.

The beneficial properties of marine polysaccharides in alleviation of allergic responses.

Marine polysaccharides have been found as the principle component in cell wall structures of seaweeds or exoskeletons of crustaceans. Due to numerous pharmaceutical properties of marine polysaccharides such as antioxidant, anti-inflammatory, antiallergic, antitumor, antiobesity, antidiabetes, anticoagulant, antiviral, immunomodulatory, cardioprotective, and antihepatopathy activities, they have been applied in many fields of biomaterials, food, cosmetic, and pharmacology. Recently, several marine polysaccharides such alginate, porphyran, fucoidan, and chitin and its derivatives have been evidenced as downregulators of allergic responses due to enhancement of innate immune system, alteration of Th1/Th2 balance forward to Th1 cells, inhibition of IgE production, and suppression of mast cell degranulation. This contribution, therefore, focuses on antiallergic properties of marine polysaccharides and emphasizes their potential application as bioactive food ingredients as well as nutraceuticals for prevention of allergic disorders.

Antioxidant and anti-inflammatory activities of porphyran isolated from discolored nori (Porphyra yezoensis).

We found that discolored waste nori with no commercial value, contains much higher level of porphyran than normal nori that is a sheeted food stuff prepared from P. yezoensis used in sushi. Chemical analyses revealed that mean molecular mass of the porphyran prepared from discolored nori (dc-porphyran) was much lower than that of the porphyran from normal nori (n-porphyran). Dc-porphyran showed slightly greater scavenging activity toward superoxide anion and hydroxyl radical than n-porphyran. Dc-porphyran inhibited nitric oxide (NO) production in LPS-stimulated RAW264.7 cells through preventing the expression of inducible NO synthase, whereas no such activity was observed in n-porphyran. Since acid-hydrolyzed n-porphyran showed the inhibitory activity on NO production from LPS-stimulated RAW264.7 cells, the molecular size of porphyran was suggested to be a critical factor for the activity. Dc-porphyran was separated into 4 fractions (F1-F4) on DEAE-chromatography, and F1 showed the highest inhibitory effect on NO production from LPS-stimulated RAW264.7 cells. Our results indicate that discolored waste nori is useful as a source of porphyran with even better bioactivities than porphyran from normal nori.

A cytotoxic type-2 ribosome inactivating protein (from leafless mistletoe) lacking sugar binding activity.

Articulatin-D, a 66 kDa ribosome inactivating protein (RIP) comprised of 29 kDa A-chain linked to 35 kDa B-chain, is purified from leafless mistletoe (Viscum articulatum) parasitic on Dalbergia sp. from Western Ghats (India). N-terminal sequence and LC-MS/MS analyses of A- and B-chain confirmed that articulatin-D is a type-2 RIP having high homology with other mistletoe lectins. Translation inhibition and diagnostic N-glycosidase activity of articulatin-D illustrate the presence of catalytically active A-chain. Its inability to: (i) bind to acid treated Sepharose CL-6B column, (ii) agglutinate trypsin-treated and untreated RBCs of human (A, B, O, AB), mice, rat, rabbit, buffalo, porcine, pigeon, cock, fish, sheep and goat even with 10mg/ml of purified articulatin-D, (iii) show change in circular dichroism spectra after addition of sugar to the native protein, (iv) bind to different sugars (galactose, lactose, gal-NAc, rhamnose, arabinose, fucose and mannose) immobilized on Sepharose 4B matrix, and (v) show change in enthalpy during titration with galactose confirm that the B-chain of articulatin-D lacks sugar binding activity. Despite this, articulatin-D is highly toxic as characterized with low IC(50) against different cancer cell lines (Jurkat: 0.31 ± 0.02 nM, MOLT-4: 0.51 ± 0.03 nM, U-937: 0.64 ± 0.07 nM, HL-60: 0.79 ± 0.11 nM, Raji: 1.45 ± 0.09 nM). Toxicity of RIPs has been ascribed to the absence/presence of B-chain with sugar binding activity. Identification of articulatin-D, the first cytotoxic RIP with B-chain lacking sugar binding activity opens new vistas in understanding cytotoxic action of RIPs.

Antioxidant and immunological activities of water-soluble polysaccharides from Aconitum kusnezoffii Reichb.

Aconitum kusnezoffii Reichb., one of the earliest recorded toxic species of genus Aconitum, has been used as traditional Chinese medicine and medicinal diet over the last 2500 years to treat heart failure congestion, neuralgia, rheumatism and gout, etc. In the present paper, four water-soluble polysaccharide fractions isolated from the tubers of A. kusnezoffii Reichb. were studied the antioxidant and immunological activities for the first time. In vitro antioxidant assays indicated that fraction WKCP-A had noticeable scavenging activities on DPPH radical, hydroxyl radical, superoxide anion, H(2)O(2) and self-oxidation of 1,2,3-phentriol, ferrous ion-chelating ability and reducing power. Moreover, the in vivo immunological assay exhibited that fractions WKCP-A and WKHP could more significantly enhance splenic lymphocyte proliferation and macrophage phagocytosis than other fractions. Therefore, the water-soluble polysaccharides from A. kusnezoffii Reichb., especially WKCP-A, have the potential to be explored as novel natural antioxidants and immunostimulating agents for using in functional foods or medicine.

Isolation and characterization of a French bean hemagglutinin with antitumor, antifungal, and anti-HIV-1 reverse transcriptase activities and an exceptionally high yield.

A dimeric 64-kDa hemagglutinin was isolated with a high yield from dried Phaseolus vulgaris cultivar "French bean number 35" seeds using a chromatographic protocol that involved Blue-Sepharose, Q-Sepharose, and Superdex 75. The yield was exceptionally high (1.1g hemagglutinin per 100g seed), which is around 10-85 times higher than other Phaseolus cultivars. Its N-terminal sequence resembled those of other Phaseolus hemagglutinins. The hemagglutinating activity of the hemagglutinin was stable in the pH range 6-8, and in the temperature range 0 degrees C-50 degrees C. It inhibited HIV-1 reverse transcriptase with an IC50 of 2microM. It suppressed mycelial growth in Valsa mali with an IC50 of 10microM. It inhibited proliferation of hepatoma HepG2 cells and breast cancer MCF-7 cells with an IC50 of 100 and 2microM, respectively. It had no antiproliferative effect on normal embryonic liver WRL68 cells.

[Effect on late-stage mammary cancer treated by endocrinotherapy or chemotherapy combined with pingxiao capsule].

OBJECTIVE: To explore the action of pingxiao capsules (PXC) and its significance in the treatment of late stage mammary cancer (LSMC). METHODS: One hundred and forty-two LSMC patients were randomized into four groups: the two single treated groups treated by endocrinotherapy (ET) alone (n = 27) and by chemotherapy alone (n=44) respectively, and the two PXC combined treated groups treated with PXC plus endocrinotherapy (n=27) or chemotherapy (n=44). The remission rate and progression time (TTP) of disease, the survival time and quality of life (QOL) of patients, and the adverse reaction were compared between the single treated groups and the combined treated groups. RESULTS: The median progression time was obviously prolonged, and QOL improved in the combined treated groups than those in the single treated groups (P < 0.05), but no significant difference was found in the remission rate or adverse reaction between them. CONCLUSION: PXC can improve QOL, prolong the progression time in patients of LSMC, and with less adverse reaction. It is worth spreading combination of PXC with chemo- or endocrino-therapy in clinical application for treatment of LSMC patients.

Free N-glycans already occur at an early stage of seed development.

As a part of our studies to elucidate the physiological significance of free N-glycans in differentiating or growing plant cells, we first demonstrate that two kinds of free N-glycans already occur at an early stage of seed development. In this report, we used the developing Ginkgo biloba seeds as a model plant, since we have already revealed a functional feature of the Ginkgo endo-beta-N-acetylglucosaminidase and structural features of N-glycans linked to storage glycoproteins in the developing seeds [Kimura, Y. et al. (1998) Biosci. Biotechnol. Biochem. 62, 253-261; Kimura, Y. and Matsuo, S. (2000) Biosci. Biotechnol. Biochem. 64, 562-568]. The structures of free N-glycans, which were determined by a combination of ESI-MS, sequential a-mannosidase digestions, partial acetolysis, and two dimensional sugar chain map, fell into two categories. One dominant species is a high-mannose type structure having one GlcNAc residue at the reducing end (Man(9-5)GlcNAc(1)). The concentration of this type of free glycan (as the pyridylaminated derivatives) is about 2.2 nmol in 1 g fresh weight. The detailed structural analysis revealed that the high-mannose type structures have a common core unit; Manalpha1-6(Man1-3)Manalpha1-6(Manalpha1-3)Ma nbeta1-4GlcNAc. The other minor species of free N-glycans is the plant complex type structure having an N-acetylchitobiose unit at the reducing end (Man(3)Xyl(1)Fuc(1)GlcNAc(2)). The concentration of this type of free glycan (as the pyridylaminated derivative) was about 75 pmol in 1 g fresh weight.

Cloning and functional activity of a novel truncated form of annexin IV in mouse macrophages.

Annexin IV was cloned and sequenced from a mouse bone marrow-derived macrophage cDNA library, and was found to exist as three different alternatively spliced transcripts. One transcript contained an additional 688 base pairs inserted within the coding region of the gene including an in-frame stop codon. Translation of this transcript in vitro confirmed the premature arrest of translation which resulted in a truncated annexin IV protein of approximately 22 kDa. Like other members of the annexin family, the product of the wild-type annexin IV transcript bound in a calcium-dependent manner to both phenyl-sepharose and phospholipid vesicles. In contrast, the truncated annexin IV product bound to these substrates in a Ca2+-independent fashion. The existence of a novel form of annexin IV in mouse macrophages may aid in further defining the role of members of the annexin family.

Purification of a multicatalytic protease complex from developing winged bean seeds by indirect immunoaffinity chromatography.

Many protease inhibitors have been characterized from leguminous seeds but very little is known about seed proteases which are supposedly regulated by these inhibitors. We have developed an indirect immunoaffinity chromatography system for the purification of cognate proteases from the same source, based on preferential high salt elution of the enzyme from a ternary complex of the protease, the inhibitor, and the anti-inhibitor IgG. Using anti-winged bean chymotrypsin inhibitor (WbCI) IgG as an affinity ligand, a multicatalytic protease complex has been purified from developing winged bean (Psophocarpus tetragonolobus) seeds. The purified preparation resolves into two large proteolytically active components when subjected to gel permeation chromatography under nondenaturing conditions, while SDS/PAGE analysis shows the presence of approximately 15 polypeptide chains in the 20- to 115-kDa range. The preparation cleaves known synthetic peptide substrates of trypsin, chymotrypsin, and V8 protease and it is only partially inhibited by a number of class-specific protease inhibitors. Western blot analysis shows the presence of WbCI in the purified preparation even after its extensive removal by the IgG-Sepharose column. The versatility of the indirect immunoaffinity chromatography system is attested by its extension to the soybean seeds.

Purification and cDNA cloning of cytokinin-specific binding protein from mung bean (Vigna radiata).

Synthetic urea derivatives such as N-phenyl-N'-(4-pyridyl)urea (4PU) and N-(2-chloro-4-pyridyl)-N'-phenylurea (4PU30) have strong cytokinin activities. Using tritiated 4PU30 as a probe, we previously established the presence of a cytokinin-specific binding protein (CSBP) of high affinity (Ka for 4PU30 = 4x10(10) M(-1)) in the soluble fraction of etiolated mung bean seedlings [Nagata, R., Kawachi, E., Hashimoto, Y. & Shudo, K. (1993) Biochem. Biophys. Res. Commun. 191, 543-549]. In this report, we purified CSBP by the use of 4PU-Sepharose 4B, an affinity gel liganded with 4PU. We determined partial amino acid sequences of CSBP and isolated its cDNA by reverse-transcription (RT) PCR. The cDNA encoded a protein with a calculated molecular mass of 17 kDa. A data base homology search revealed that CSBP is a novel member of a major pollen allergen/pathogenesis-related protein family. Recombinant CSBP was expressed in Escherichia coli and was confirmed to bind specifically to cytokinins.

Evidence for a DNA homologous pairing activity in nuclear extracts from mosquito cells.

Using a sensitive homologous pairing/DNA strand transfer assay, we detected formation of joint molecules in the presence of nuclear extract from cultured mosquito C7-10 cells in a reaction containing single stranded circular m13 DNA and a linear, double stranded DNA 5'-end-labeled on the strand complementary to a portion of the single-stranded substrate. Joint molecules were detected by the reduced electrophoretic mobility of labeled probe on agarose gels, which indicated that the 5'-end labeled strand of the linear duplex had formed a hybrid with the single-stranded substrate. Characterization of the activity detected initially in crude nuclear extracts provided a basis for a 5-fold enrichment of activity after a two-step KCl elution from heparin-Sepharose. Further purification by preparative electrophoresis yielded a band at approximately 35 kDa, which, when transferred to Immobilon P membrane, specifically bound the labeled, complementary strand probe. Optimal activity of the electroeluted enzyme required both magnesium and ATP and was sensitive to the ratio of single-stranded and double-stranded DNA substrate and to the amount of protein. This homologous pairing activity from mosquito cells is the first such activity to be described from an insect other than Drosophila melanogaster.

Partial purification of a pea seed DNA-binding protein that specifically recognizes 5-methylcytosine.

Previously, a DNA-binding protein (DBPm) was identified in plant nuclei that may mediate the effects of DNA methylation on chromatin structure and transcription. In the present report, DBPm was partially purified from germinated pea (Pisum sativum) seed nuclear extracts by DEAE-cellulose, phenylsepharose, heparin-sepharose chromatography, and preparative mobility shift on polyacrylamide gels. The purified activity showed a band at approximately 50 kD by sodium dodecyl sulfate-polyacrylamide gel electrophoresis as well as by Sephadex G100 chromatography, suggesting that DBPm is present as a monomer.

The interaction of a glycosaminoglycan, heparin, with HIV-1 major envelope glycoprotein.

We demonstrate in vitro the occurrence of a specific but low-affinity interaction between soluble tetrameric rgp160 or soluble monomeric or tetrameric rgp120 and heparin-agarose (HA). This interaction is saturable, pH and temperature-dependent, and can be inhibited by soluble heparin, but not by soluble dextran. In buffer supplemented with 10 mM CaCl2, the C50 of soluble heparin, i.e., the concentration of soluble heparin which leads to 50% inhibition of the binding of [125I]rgp160 or of [125I]rgp120 to HA, is 1.1 x 10(-4) disaccharidic molar concentration for rgp160 and 3.2 x 10(-4) dissacharidic molar concentration for rgp120, which indicates low-affinity interactions. Upon chromatography on HA, [125I]rgp160 is repeatedly eluted as a retarded fraction when compared to the elution volume of [125I]rgp160-soluble heparin complex. Under the same experimental conditions, [125I]rgp120 is also eluted, but as a less retarded fraction than [125I]rgp160. Taken together, these results suggest that, at least part of the described anti HIV-1 activity of heparin might be mediated by interaction with HIV-1 major envelope glycoprotein.