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P Berlin

Publications and source records attributed to P Berlin.

12 recordsLinked to original sources
PubMed2004

Biomolecule-compatible support structures for biomolecule coupling to physical measuring principle surfaces.

As part of studies on biomolecule-compatible interfacial structures for practice-relevant biosensor and biochip developments, new film-forming aminocelluloses of the 'P-CH2-NH-(X)-NH2' type (P = cellulose) with spacer structures (X = special oligoamine residues) at C6 and solubilising groups (S = tosylate or carbanilate) at C2C3 of the anhydroglucose unit (AGU) were synthesised and their film properties and covalent coupling with enzyme protein examined. Depending on the nature and degree of substitution (DS(S)) of the ester groups (S) at C2C3, the new aminocellulose derivatives are soluble either in DMA and DMSO (with S = carbanilate) or in water (with S = tosylate). The aminocellulose derivatives form transparent films from their solutions. AFM investigations of the film surfaces have either shown very flat (topography <1 nm) films or tubular topographies of nanostructure size, depending on structural and environment-induced factors of influence. Especially in the case of films from water-soluble aminocelluloses with oligoamine residues at C6, inter alia, enzyme-specific pH values and different positive charge distributions can be adjusted by partial protonation of the NH2 end groups. By means of the covalent coupling of the new aminocelluloses with glucose oxidase (GOD) it was shown that the enzyme coupling efficiency can be decisively optimised by the interplay of aminocellulose structure, coupling structure and enzyme protein.

Journal Article↗
PubMed1999

A novel efficient enzyme-immobilization reaction on NH2 polymers by means of L-ascorbic acid.

A new enzyme-immobilization reaction by means of L-ascorbic acid (ASA) is described using NH(2) polymers based on cellulose or poly(vinyl alcohol) with the example of oxidoreductase enzymes. In this way, enzyme proteins such as glucose oxidase (GOD), glutamate oxidase, lactate oxidase, urate oxidase and peroxidase can be covalently fixed with a high surface loading to ultrathin and transparent NH(2)-polymer films if their surfaces are previously treated with an ASA solution, in, for example, N,N-dimethyl acetamide, DMSO or methanol. ASA then obviously reacts like a diketo compound with amino groups of the NH(2)-polymer film and enzyme protein, forming dehydroascorbic acid derivatives with neighbouring Schiff's-base structures. In a subsequent fragmentation reaction, the latter presumably form stable oxalic acid diamide derivatives as coupling structures between enzyme protein and NH(2)-polymer film, as suggested by results from investigations of the ASA reaction with n-butylamine. The immobilized enzymes can be stored at 4 degrees C in bidistilled water for at least 1 month without becoming detached from the NH(2)-polymer film and without diminished enzyme activity. The apparent K(m) values of the immobilized enzymes are in part clearly smaller than those of the dissolved enzymes or those found in other immobilization processes such as the diazo coupling or the bifunctional glutardialdehyde reaction. For example, the K(m) value of the immobilized GOD with different NH(2) polymers as the matrix structure is smaller by a factor of approx. 20 than that of the dissolved enzyme.

Acetamides↗
PubMed1984

[Estimation of the effects of cardenolides. 1. Relation between molecular physical parameters and parameters of action of cardenolides].

Knowing the modell developed by Repke and co-workers for the cardenolide-receptor-interaction the aim of this study was to find quantitative relations between molecular physical properties of cardenolides and their molecular-biologically defined effect, which are fundamentally useful to estimate the effect of still nonsynthesized cardenolide derivatives. The statistically significant relations (alpha = 0.05) between molecular physical parameters, which are derived from the dipole moment vector, and the molecular-biologically defined effect was found by means of regression analysis.

Adenosine Triphosphatases↗
PubMed1984

[Estimation of the intensity of effect of cardenolides. 2: Algorithms for the estimation of the intensity of effect].

An algorithm worked on basis of quantitative relations between molecular-biologically defined effects and molecular-physical properties (see part 1) allows the effect estimation of concepted cardenolides before their synthesis. The empirical use of the developed equations for the estimation of molecular-biologically defined effect of compounds produces usable results and justifies therefore the proposed method, as well as it's shown by the experimental proof of estimated values of some cardenolides . An enlargement of the use of the algorithm for effect estimation seems to be successful.

Cardenolides↗