Lars Gustaf Andersson

Imprinting of amino acid derivatives in macroporous polymers

Abstract Phenylalanine ethyl ester-selective polymers have been prepared using the ion-pair association of substrate and carboxyl-containing vinyl monomers in the polymerization step.

Separation of Isozymes of horse liver alcohol dehydrogenase and purification of the enzyme by affinity chromatography on an immobilized AMP-analogue

Abstract A mixture of the two homogeneous isozymes EE and SS of horse liver alcohol dehydrogenase (alcohol: NAD + oxidoreductase, EC 1.1.1.1) was separated on a column of N 6 -(6-aminohexyl)-AMP substituted Sepharose with a linear gradient of NAD + at pH 7.5 in the presence of 1.5 mM cholic acid. SS was eluted first at 0.4 mM NAD + , and EE later at 3.4 mM NAD + . This separation is due to true biospecific adsorption since both isozymes showed no affinity to a gel to which n -hexylamine had been covalently bound. From a horse liver crude extract alcohol dehydrogenase could be purified in a one-step procedure using a pulse of 0.1 mM NAD + plus 1.1 mM pyrazole resulting in 22 times purification with a yield of 36%. The enzyme obtained was homogeneous on dodecylsulphate-gel electrophoresis and showed a specific activity of about 3.1 units/mg when measured at pH 10.0.

Synthesis of a new amino acid based cross-linker for preparation of substrate selective acrylic polymers

Abstract The synthesis of N,O-bisacryloyl-L-phenylalaninol is described as well as its application in the preparation of a L-phenylalanine ethyl ester selective acrylic polymer.

Preparative purification of homogeneous steroid-active isozyme of horse liver alcohol dehydrogenase by affinity chromatography on an immobilized AMP-analog

Abstract The homogeneous steroid-active isozyme, SS, of horse liver alcohol dehydrogenase was purified preparatively from a horse liver crude extract by affinity chromatography on N 6 -(6-aminohexyl)-AMP-substituted Sepharose after a batch-wise prepurification on CM-cellulose. The enzyme obtained showed only one band on agarose-gel electrophoresis and on dodecyl sulphate-gel electrophoresis; the yield was about 30 mg SS isolated from 260 g horse liver.

IMMOBILIZED PANCREATIC LIPASE AND COLIPASE FOR PURIFICATION AND BINDING STUDIES

For fat digestion to occur a 1: 1 lipase-colipase complex is required at the oil-water interphase [l--4]. Therefore, studies of lipase-colipase interactions which occur in solution may be important. Direct studies of lipase colipase binding in the absence of substrate have been few and and as the dissociation constant is weak, 5 X lo-’ M [5], binding cannot be detected by gel filtration unless very high concentrations are used [6]. Standard purifications of the two proteins include at least 6 time-consuming steps [7-91. Although immobilization of enzymes has undergone rapid growth [lo], systems employing immobilized proteins for the isolation of other proteins have mostly been restricted to the serine proteases and their inhibitors [ 11 ,121. In this study we have immobilized porcine pancreatic lipase and colipase individually on Sepharose using a conventional technique [ 131. Affinity columns of the immobilized cofactor or enzyme provide rapid means for purification of the analogous protein as well as a sensitive technique for studying the characteristics of their binding.

The use of biochemical solid-phase techniques in the study of alcohol dehydrogenase. 1. Some studies on subunit interactions in alcohol dehydrogenase with subunits covalently bound to agarose.

The EE and SS isozymes of horse liver alcohol dehydrogenase have been immobilized separately to weakly CNBr-activated Sepharose 4B. The resulting immobilized dimeric preparations lost practically all of their activity after treatment with 6 M urea. However, enzyme activity was regenerated by allowing the urea-treated Sepharose-bound alcohol dehydrogenase to interact specifically with either soluble subunits of dissociated horse liver alcohol dehydrogenase or soluble dimeric enzyme. The regeneration of steroid activity in the immobilized preparations after treatment of the bound S subunits with soluble E subunits seems to show that true reassociation of the enzyme had taken place on the solid phase, since only isozymes with an S-polypeptide chain are active when using 5 beta-dihydrotestosterone as substrate. The results presented in this paper indicate that immobilized single subunits of horse liver alcohol dehydrogenase are inactive and that dimer formation is a prerequisite for the enzymic activity.

Purification and characterization of chicken liver alcohol dehydrogenase

Liver alcohol dehydrogenase from several species has been isolated and thoroughly studied [ 1 ]. The structures of corresponding yeast [2], Drosophila [3] and bacillar [4] enzymes have also been investigated. All enzymes appear related [3 -7 ] , but differences are extensive and affect functionally important residues, subunit interactions and other structural characteristics [5,7]. In general, the most conserved regions involve areas around the active site, including the ligands to the catalytic zinc atom. The region around the 2nd zinc atom, however, is more variable [5,7] and its ligands may even be missing [3], or involved in transitions between different sub-forms of the enzyme [8]. The aim of the present work was to purify chicken liver alcohol dehydrogenase, and to study the relationship of this previously uncharacterized protein to other alcohol dehydrogenases. To prepare the enzyme, general ligand affinity chromatography on a Sepharosebound AMP-analogue was used [9,10]. The structures around the cysteine residues are of special importance, since cysteine residues contribute 6 of the 7 zinc ligands in the horse enzyme [ 11 ] and occur in both the relatively constant and the more variable regions [7]. Therefore, the chicken enzyme was purified, its cysteine residues were radioactively labelled by carboxymethylation, and after tryptic digestion all small and medium-sized radioactive peptides were analyzed. It was found that the enzyme is distinctly similar to that from mammalian livers, and that it fits the general evolutionary pattern and functional properties of alcohol dehydrogenases suggested from studies of these proteins fron non-avian sources.

Editorial : Film Workshops in Europe

An introduction is presented in which the authors discuss various reports within the issue on topics including the concept of film workshops, the politicized film culture in Spain, and the British ...

The cultural policies of minor cinema practices: The Swedish film workshop during its first years 1973–76

ABSTRACT The essay is a description of the first years of the Stockholm film workshop, Filmverkstan, founded in 1973. The activities of the workshop are put into the framework of the new cultural policies of Sweden and the question of cultural democracy, as well as alternative ways of producing and distributing film. The output of the early years is set into generic and film historical contexts, connected to the problems of amateur film and minor cinema. One key topic is how this new venue for alternative film production was able to function together with other agencies, for example, the Swedish Film Institute, the Swedish Broadcasting Corporation and the FilmCentre coop. The essay offers an analysis of the implementation of state cultural policies within an alternative production context, the avant-garde and the alternative as a modified state apparatus.

Spaces of becoming: the Stockholm Film Workshop as a transnational site of film production

The aim of the essay was to present the Stockholm Film Workshop (Filmverkstan, 1973–2001) and its significance as a transnational site of film production. The films and the filmmaking at the workshop are considered as part of a minor cinema film practice in David E. James’s sense. James’s theory is complemented by returning to Gilles Deleuze and Felix Guattari’s original concept of minor literature in order to stress an analysis that is based on film as a means of production and cultural intervention. This point is emphasized by a presentation and analysis of how various professional and non-professional filmmakers from Colombia, Egypt, Greece and Turkey made use of film at the Stockholm Film Workshop in order to intervene in their new cultural situations. Thus, the textual model of film analysis that is prevalent in Hamid Naficy’s seminal work on accented cinema is complemented with theories of cultural production in order to enable an analysis of a transnational film practice that is on a par with the immigrant experience.