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Biomedical subjects

B Heinz

Publications and source records attributed to B Heinz.

35 records · Page 2Linked to original sources
PubMed1988

The chemical logic of a minimum protocell.

Traditional schemes for the origin of cellular life on earth generally suppose that the chance assembly of polymer synthesis systems was the initial event, followed by incorporation into a membrane-enclosed volume to form the earliest cells. Here we discuss an alternative system consisting of replicating membrane vesicles, which we define as minimum protocells. These consist of vesicular bilayer membranes that self-assemble from relatively rare organic amphiphiles present in the prebiotic environment. If some of the amphiphiles are primitive pigment molecules asymmetrically oriented in the bilayer, light energy can be captured in the form of electrochemical ion gradients. This energy could then be used to convert relatively common precursor molecules into membrane amphiphiles, thereby providing an initial photosynthetic growth process, as well as an appropriate microenvironment for incorporation and evolution of polymer synthesis systems.

Cells↗
PubMed1981

The formation of chromophores through amino acid thermolysis and their possible role as prebiotic photoreceptors.

The thermal polymerization of amino-acid mixtures was studied at various temperatures and reaction times with specific emphasis on the formation of fluorescent chromophores. The reaction conditions appeared to have a pronounced effect on the ratio of synthesized chromophores and biuret-positive material. During thermolysis of equimolar mixtures of lysine, alanine and glycine or lysine, aspartic acid and glycine small amounts of pteridines and flavines are formed, which are often covalently linked to the thermal oligomer. These heterocyclic compounds are likely formed by condensation reactions of the amino acid break-down and conversion products. Reaction schemes that describe the processes are proposed. The significance of these chromoproteinoids is discussed in respect to prebiotic redox reactions and photoinduced processes.

Amino Acids↗