THE MOLECULAR WEIGHT OF HAEMATOPORPHYRIN DERIVATIVE, ITS GEL COLUMN FRACTIONS and SOME OF ITS COMPONENTS IN AQUEOUS SOLUTION

Abstract— The average molecular weights of haematoporphyrin derivative (HPD), the fractions of HPD that can he obtained by gel chromatography and of purified haematoporphyrin and protoporphyrin in aqueous solution have been determined by ultracentrifugation. The results show that HPD contains polymeric material with the excluded fraction from the gel column (HPD aggregate) having an average molecular weight of greater than 20000. The two remaining gel column fractions of HPD have lower molecular weights and their similarity indicates that these fractions do not separate because of molecular weight differences. Purified haematoporphyrin has a comparatively low molecular weight in aqueous solution but the data is not capable of discriminating between monomer, dimer or slightly higher oligomer. In contrast, protoporphyrin sediments to the bottom of the centrifuge tube under the conditions of sedimentation equilibrium indicating that it has an average molecular weight considerably greater than that of HPD aggregate.     

血卟啉衍生物的色谱分离

本文拟定的纸色谱法是以苯-乙酸乙酯-甲醇-乙酸(9:2:1:1)作展开剂,将血卟啉衍生物(HPD)分离为五部份,分别测定各部份浸取液的荧光发射光谱,作为一种对血卟啉衍生物组份作对比鉴定的参考方法。采用Ward的高效液相色谱程序对比研究结果表明,国产与美国产HPD的组份近似,均以血卟啉为主要组份,而前者血卟啉的含量较高;二者还均含有羟乙基乙烯基衍生物和羟基乙酸酯,初步研究了血卟啉衍生物在甲醇-水溶剂系统中的高效液相色谱行为,进一步将血卟啉衍生物分离为九部份,有利于单一组份研究。     

Single crystals of cellulose IVII: Influence of the cellulose molecular weight

The influence of the degree of polymerization (DP) of cellulose was evaluated in the preparation of micron-sized cellulose IV_II lamellar crystals in order to ascertain whether a regular chain-folded morphology could develop during their growth. For this purpose, sharp fractions of cellulose acetate were collected by preparative gel permeation chromatography. Aliquots of these fractions were deacetylated and crystallized in dilute solutions containing water, methylamine, and DMSO, and held at 150°C under pressure. Well-developed cellulose IV_II lamellar crystals were obtained with fractions of DP 22–24 whereas higher-DP material gave polycrystalline aggregates. This behavior indicates that large lamellar crystals of cellulose IV_II can be obtained only with unfolded short cellulose chains. The occurrence of chain-folded crystals with high–DP cellulose samples cannot be demonstrated.     

PRODUCTION OF PEPTIDE COMPOUNDS FROM ETHYLENE GLYCOL AND HYDROXYLAMINE BY RADIATIONINDUCED SYNTHESIS*

Abstract Aqueous solutions of ethylene glycol and hydroxylamine in a 10:1 weight ratio were irradiated with an immersion-type mercury-vapour lamp, under static and dynamic conditions. The photochemical products obtained were fractionated by means of ion-exchange resins, gel filtration on Sephadex G 10, paper chromatography, and thin-layer chromatography. Biuret reaction was carried out on the various fractions, and different nitrogen forms as well as amino acids, before and after hydrolysis, were determined. Irradiation was found to bring about the formation of a number of organic compounds, including peptides. The yields of these compounds were determined in relation to the concentration and the flow rate of the solutions. The yields increased with increase in the two variables. The fractions richest in peptide compounds, coming from gel-filtration and thin-layer chromatography, were studied by the technique of DNP-derivatives. The constituent amino acids were found to be glycine, β-alanine, α-alanine, glutamic acid and leucine. The average length of the chains contained 7 amino acids.     

Comparison by gel filtration chromatography and reversed-phase high-performance liquid chromatography of the immunoreactive growth hormone composition of a human pituitary extract

The immunoreactive growth hormone composition of a pituitary extract has been compared by conventional gel filtration chromatography (pH 8), and reversed-phase high-performance liquid chromatography (pH 2) on a wide-pore (300 A) short-chain column. By gel filtration chromatography, four peaks of immunoreactivity were obtained, labelled "monomer", "dimer", "aggregate" and "void". However, by high-performance liquid chromatography all of these fractions were themselves shown to be multicomponent mixtures. The "monomer" peak contained at least two forms (M1 and M2). The "dimer" fraction contained three peaks, two of which co-eluted with M1 and M2, and a third component, D. Similarly, the aggregate fraction contained M1, M2, D and a fourth component, A. The "void", in contrast, contained mostly M1 and M2 with very little D. One interpretation of these results is that M1 (the 22K molecular weight monomeric form) and M2 (a chemically modified form of M1) are present in all molecular weight fractions in loosely bound aggregates which break up under acidic conditions. D and A are probably oligomeric forms of growth hormone (possibly a dimer and higher molecular weight species, respectively).     

Anti-Cancer Activity of Buthus occitanus Venom on Hepatocellular Carcinoma in 3D Cell Culture

Hepatocellular carcinoma (HCC) is the most dominant primary liver cancer, which can be caused by chronic hepatitis virus infections and other environmental factors. Resection, liver transplantation, and local ablation are only a few of the highly effective and curative procedures presently accessible. However, other complementary treatments can reduce cancer treatment side effects. In this present work, we evaluated the activity of Moroccan scorpion venom Buthus occitanus and its fractions obtained by chromatography gel filtration against HCC cells using a 3D cell culture model. The venom was fractionated by gel filtration chromatography, each fraction and the crude venom was tested on normal hepatocytes (Fa2N-4 cells). Additionally, the fractions and the crude venom were tested on MCTSs (multicellular tumor spheroids), and this latter was generated by cultivate Huh7.5 cancer cell line with WI38 cells, LX2 cells, and human endothelial cells (HUVEC). Our results indicate that Buthus occitanus venom toxin has no cytotoxic effects on normal hepatocytes. Moreover, it is reported that F3 fraction could significantly inhibit the MCTS cells. Other Protein Separation Techniques (High-performance liquid chromatography) are needed in order to identify the most active molecule.     

PHOTOCHEMICAL-LIKE BEHAVIOUR OF RIBOFLAVIN IN THE DARK PROMOTED BY ENZYME-GENERATED TRIPLET ACETONE

Abstract— Triplet acetone obtained enzymically by the isobutyraldehyde/peroxidase/O₂ system transfers its energy to the riboflavin, which changes into a decomposition product of lumichrome type and produces aggregates. When riboflavin and tryptophan are added to this system, further products—formylkynurenine and an adduct between the riboflavin and the tryptophan—are formed. The adduct can be separated by gel filtration and ion exchange chromatography and is similar to that prepared by irradiating riboflavin in the presence of tryptophan.     

两亲性梳状聚醚硅氧烷对相转化法聚偏氟乙烯多孔膜的共混改性作用研究

以聚醚链段为侧链的两亲性梳状聚醚硅氧烷(ACPS)为改性剂,研究了相转化法制备聚偏氟乙烯(PVDF)多孔膜的改性效果与机理.采用SEM、XPS、接触角、水通量等考察了ACPS对膜结构与性能的影响.研究发现,ACPS在相转化成膜过程中不流失,随着制膜液中ACPS含量的增加,相分离速度降低,膜中微孔由指状结构向蜂窝状结构发展,膜强度提高,亲水性显著提高.提出了ACPS在膜表面的富集现象和在膜中的稳定性机理和模型.结果表明,两亲性梳状聚醚硅氧烷在原理上是一类适合于相转化法制备聚合物微孔膜表面亲水化改性的有效物质.     

GEL PERMEATION CHROMATOGRAPHIC ANALYSIS OF LACQUER POLYSACCHARIDE

Ten fractionated samples of Chinese lacquer polysaccharide in aqueous 0.1M NaC1 solution were studied by aqueous-phase gel permeation chromatography (GPC). The universal calibration, broad MWD calibration and corrected column dispersion were adopted to the analysis of GPC chromatograms of the polysaccharide. The molecular weights M_w, M_n and polydispersity index M_w/M_n obtained from GPC are in good agreement with the results of light scattering and membrane osmometry. It is verified that the universal calibration concept is applicable to the lacquer polysaccharide having a number of side chains.     

Well-defined nanoparticles formed by hydrophobic assembly of a short and polydisperse random terpolymer, amphipol A8-35

Amphipols are short amphilic polymers designed for applications in membrane biochemistry and biophysics and used, in particular, to stabilize membrane proteins in aqueous solutions. Amphipol A8-35 was obtained by modification of a short-chain parent polymer (poly(acrylic acid); PAA) with octyl- and isopropylamine, to yield an amphiphilic product with an average molar mass of 9-10 kg x mol(-1) (sodium salt form) and a polydispersity index of 2.0 to 3.1, depending on the source of PAA. The behavior of A8-35 in aqueous buffers was studied by size exclusion chromatography, static and dynamic light scattering, equilibrium and sedimentation velocity analytical ultracentrifugation, and small angle neutron scattering. Despite the variable length of the chains and the random distribution of hydrophobic groups along them, A8-35 self-organizes into well-defined assemblies. The data are best compatible with most of the polymer forming compact assemblies (particles) with a molar mass of approximately 40 kg x mol(-1), a radius of gyration of approximately 2.4 nm, and a Stokes radius of approximately 3.15 nm. Each particle contains, on average, four A8-35 macromolecules and 75-80 octyl chains. Neutron scattering reveals a sharp interface between the particles and water. A minor (approximately 0.1%) mass fraction of the material forms much larger aggregates, whose proportion may increase under certain conditions of preparation or handling, such as low pH. They can be removed by gel filtration.     

亲水/疏水半互穿网络凝胶在直流电场作用下的响应

研究了一种亲水 疏水型半互穿网络水凝胶 (PAAc QPVPDgels)对直流电场的刺激应答 .该凝胶中的疏水型N 十二烷基聚 (4 乙烯吡啶 )溴化盐 (QPVPD)高分子链与亲水型聚丙烯酸水凝胶 (PAAc)网络通过物理缠绕复合 .由于疏水力和亲水力的共同作用 ,在接触电场下 ,该凝胶在阳极端发生消溶胀 ,疏水相互作用对消溶胀有一定的影响 ;在非接触电场下 ,该凝胶在弱碱性溶液中迅速向阴极方向弯曲 ,在弱酸性溶液中首先发生消溶胀 ,然后向阳极方向弯曲     

红外光谱法研究镍顺丁橡胶分级样品及凝胶的微结构

顺丁橡胶的链结构与其溶液性质和物理性能有密切关系,凝胶的存在往往影响加工和使用性能。付里叶变换红外光谱技术的发展使我们有可能考察顺丁分子链微结构与分子量的关系,研究凝胶与线性分子链结构的差别。     

Selective initiation of nonconjugated dienes containing electron donor–electron acceptor systems. IV. Polymerization of vinyl ether–styrene monomers

Three isomeric nonconjugated dienes, o-, m- and p-(2-vinyloxyethoxy)styrenes, were selectively polymerized by anionic or radical initiators through the styryl double bond while leaving the vinyl ether moiety intact. The anionic-initiated polymeric products are of high molecular weight and narrow molecular weight distribution as characterized by membrane osmometry and gel-permeation chromatography, respectively. These polymers were subsequently crosslinked by cationic initiators via the vinyl ether moiety on the polymer side chains. Acid-catalyzed hydrolysis of the poly(2-vinyloxyethoxy)styrenes yielded their respective hydroxy-containing polymers, polyvinylphenoxyethanols. The latter were physically and spectroscopically identical to authentic samples prepared by radical polymerization of the corresponding vinylphenoxyethanols, which, in turn, were synthesized by hydrolysis of the (2-vinyloxyethoxy)styrenes. The polyvinylphenoxyethanols were shown to undergo many chemical transformations, such as esterification with 3,5-dinitrobenzoyl chloride, cyanoethylation, and urethane formation.     

Quaternary size distribution of soluble aggregates of glutathione-S-transferase-purified viral protein as determined by asymmetrical flow field flow fractionation and dynamic light scattering

Polyomavirus VP1 protein in pentamer form was expressed in E. coli and purified using glutathione-S-transferase (GST) affinity chromatography. Purified GST-tagged protein was found to exist as soluble aggregates with a size distribution of 1-52 tagged pentamers (340-1800 x 10(3)kDa), as determined by asymmetrical flow field flow fractionation with multiple angle light scattering (AFFFF-MALS). Aggregation did not inhibit tag removal by enzymatic cleavage, implying that the quaternary structure of the VP1 pentamers had been maintained. Elution gel filtration (EGF) was utilized to prepare a solution enriched with protein small enough to access resin pores (LMWe) as well as solution enriched with protein excluded from resin pores (HMWe). Material size distributions within both solutions were determined using AFFFF-MALS (radius of gyration LMWe: 5-10nm; HMWe: 10-35 nm) and dynamic light scattering (DLS) (hydrodynamic diameter LMWe: 10-90 nm; HMWe: 20-300 nm). DLS and AFFFF-MALS analysis of each fraction of affinity chromatography purified material identified the elution profiles of large and small aggregate structures. DLS readings of all fractions were significantly affected by the presence of high molecular weight aggregates, with Z-average hydrodynamic diameter values reflecting the mass ratio of large and small aggregate structures in a solution. The methods utilized in this study have the potential to be used during chromatographic purification of all proteins that exist as soluble aggregates to determine size distribution. The finding that GST-tagged viral proteins exist as soluble aggregates has implications for existing immunological studies that utilize them.     

Purification and characterization of transglutaminases from the genital tract of the male rat.

In the genital tract of the male rat two different forms of the enzyme transglutaminase (TGase) could be identified and characterized. The coagulating gland and the dorsal prostate secrete a glycosylated and acylated TGase with a molecular weight of 65,000 dalton and pI value of 8.7. This secretory form was purified to homogeneity using preparative isoelectric focusing and gel filtration on a Superdex 200 column. Running fast protein liquid chromatographic gel filtration on a Superose 12 column in the presence of calcium ions, high-molecular-weight aggregates were physically formed which could only be eluted using drastic conditions (0.1 M sodium hydroxide). In the presence of 10 mM EDTA this tendency to aggregate was greatly diminished. Utilizing a Superdex 200 column for gel filtration, the secretory TGase was even eluted as a monomeric protein. Testicular TGase was isolated by ion-exchange fast protein liquid chromatography on a Mono Q and by gel filtration on a Superdex 200 column. This enzyme represents a tissue-type TGase with a molecular weight of 82,000 dalton and pI value of 5.25. Hydrophobic interaction chromatography on a phenyl-Superose column showed no further enrichment of the GTP-binding form of transglutaminase.     

Synthesis and Structural Characterization of a Polyphosphazeneas Photoconductivc Material

n the past decades, photoconductive polymers have received much attention either from atlindamental standpoint or for their potential uses ]' 2. The photoconductivities of manypolymers have been reported, such as phenylmethylpolysilane, poly(pphenylenevinylene ), N-poly(vinylcarbazole ), and so on.Recently we have synthesized a novel polyphosphazene that contains chargetransporting agent for photoconductive application. Polyphosphazene was selectedbecause of its photochemical stability, the go…     

Synthesis and gas permeation properties of poly(vinyl chloride)‐graft‐poly(vinyl pyrrolidone) membranes

A series of amphiphilic graft copolymers consisting of poly(vinyl chloride) (PVC) main chains and poly(vinyl pyrrolidone) (PVP) side chains, i.e. PVC‐g‐PVP, was synthesized via atom transfer radical polymerization (ATRP), as confirmed by ¹H NMR, FT‐IR spectroscopy, and gel permeation chromatography (GPC). Transmission electron microscope (TEM) and small angle X‐ray scattering (SAXS) analysis revealed the microphase‐separated structure of PVC‐g‐PVP and the domain spacing increased from 21.4 to 23.9 nm with increasing grafting degree. All the membranes exhibited completely amorphous structure and high Young's modulus and tensile strength, as revealed by wide angle X‐ray scattering (WAXS) and universal testing machine (UTM). Permeation experimental results using a CO₂/N₂ (50/50) mixture indicated that as an amount of PVP in a copolymer increased, CO₂ permeability increased without the sacrifice of selectivity. For example, the CO₂ permeability of PVC‐g‐PVP with 36 wt% of PVP at 35°C was about four times higher than that of the pristine PVC membrane. This improvement resulted from the increase of diffusivity due to the disruption of chain packing in PVC by the grafting of PVP, as confirmed by WAXS analysis. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and Structural Characterization of a Polyphosphazeneas Photoconductive Material

The synthesis of a novel polyorganophosphazene that contains charge-transporting agent as side chains for photoconductive application is reported. Structural characterization for the high polymer was presented by 1H-NMR, infrared spectrosocopy, gel permeation chromatography ( GPC ).     

Solution behavior of two liquid crystalline polymers of different architectures

Solutions of two different liquid crystalline polymers of high molecular weight are investigated by static and dynamic light scattering (LS), membrane osmometry and size-exclusion chromatography (SEC). Measurements in dilute solution in different solvents showed no specific behavior as formation of aggregates or chain stiffening. Large discrepancies between the LS results and the results from osmometry and SEC show that the latter methods are in the present cases not suitable for molecular weight determination. In semi-dilute solution the osmotic modulus and the time correlation function were studied. Behavior of flexible chains was observed. In one system a slight aggregation of small molecules onto longer chains was found causing less interpenetration of the chains in that solvent. At moderately high concentrations cluster formation was observed from i) a small angle excess scattering, ii) a downturn of the osmotic modulus, and iii) the appearance of a slow motion in the time-correlation function.     

Chemical Interactions of Cryptic Actinomycete Metabolite 5‐Alkyl‐1,2,3,4‐tetrahydroquinolines through Aggregate Formation

Organisms often produce secondary metabolites as a mixture of biosynthetically related congeners. However, why are metabolites with minor chemical variations produced simultaneously? 5‐Alkyl‐1,2,3,4‐tetrahydroquinolines (5aTHQs) are small, lipophilic metabolites produced by Streptomyces nigrescens HEK616 when cultured with Tsukamurella pulmonis TP‐B0596. A mixture of 5aTHQs forms aggregates that show enhanced membrane affinity and biological activity. The ability to form aggregates and membrane‐binding activity is regulated by the length of the alkyl chains. Aggregates with long alkyl chains were too stable to fuse with lipid membranes. However, if inactive 5aTHQ congener was mixed with active congener, the mixture showed increased membrane affinity, enabling cellular entry and biological activity. Therefore, it is shown that sloppiness in a biosynthetic pathway, by which minor structural variations can be produced, is functionally rational, as the metabolites show synergistic action.