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BUILDING BLOCKS FOR THE CHEMICAL SYNTHESIS OF DNA CONTAINING C(3')-CH2-P BONDS
No full textThe preparation, starting from glucose, of 3'-[ (2-chlorophenoxy)phosphinylmethyl]-
N2-isobutyryl-5'-0-(4-methoxytrityl)-2' ,3'-dideoxyguanosine ts
described. Applying established phosphotriester methods, 21 was used to synthesize
a phosphonate analogue of the dinucleotide monophosphate d(G-C)
ANWENDUNG VON MEMBRANEN BEI DER PRODUKTION VON ACETON UND BUTANOL DURCH CLOSTRIDIUM ACETOBUTYLICUM IN EINER KONTINUIERLICHEN KULTUR
No full textZur fermentativen Aceton-Butanolproduktion ohne Kulturdegenerierung und mit möglichst
hoher Lösungsmittel-Produktivität wurde ein zweistufiges Kaskadensystem entwickelt.
In der ersten Stufe der Kaskade wird die Kultur beim Umpumpen durch ein kapillarförmiges
Cross-f low-Mikrofiltrationsmodul scherkraftaktiviert. Solche aktivierten Kulturen
haben im Vergleich zu konventionellen Chemostatkulturen eine wesentlich höhere
spezifische Lösungsmittelproduktivität, spezifische Glucoseverbrauchsrate und spezifische
Wachstumsrate. Zur Erhöhung der Raum-Zeit-Ausbeute wird in der zweiten Stufe
der Kaskade ebenfalls ein kapillarformiges Cross-flow-Mikrofiltrationsmodul zwecks
Kulturaktivierung und gleichzeitiger Zellrückführung eingesetzt. In der zweiten Kaskadenstufe
wurde die Zellkonzentration turbidostatisch geregelt. Bei einer kontinuierlichen
Fermentation mit glucosehaltigem Medium wurden Lösungsmittelproduktivitäten
von 3 bzw. 2,3 g Los. yl bei Lösungsmittelkonzentrationen von etwa 12 bzw.
15 git erreicht
MEMBRANTRENNVERFAHREN ALS INSTRUMENT ZUR PROZESSANALYTIK VON ENZYMEN
No full textDie Analytik von Enzymen in biotechnologischen Prozessen ist von steigender Bedeutung
im Zuge der Optimierung von Produktionsprozessen. Für die Bestimmung der Enzyme
werden in der Regel naßchemische Methoden offline angewendet mit entsprechendem
Aufwand und Zeitverzug. Der vorliegende Beitrag zeigt Ansätze, wie unter Einbau von
Membrantrennverfahren eine kontinuierliche Online-Analytik für Enzyme in der Fermentation
und der Aufarbeitung aufgebaut werden kann
FLUORESCENCE-BASED OPTOCHEMICAL SENSORS (OPTODES) AND RELATED BIOSENSORS USING ENZYME-CATALYZED BIOCHEMICAL AND ANTIBODY-LINKED IMMUNOLOGICAL REACTIONS
No full textThe principles and some technical properties of fluorescence-based optochemical sensors
(optodes) involving membrane-protected O9- and pH-sensitive fluorescent indicator
molecules are presented for the continuous measurement of oxygen, carbondioxide
and hydrogen ion activities as well as ionic strength. Moreover, sensor-coupled biochemical
and immunological reactions, which enable the quantitative determination of
various metabolites and hormones on the basis of enzyme-mediated reactions and antigen-
antibody interactions are discussed. Finally, some advantages and special features
of this new sensor technology are presented in comparison to the conventional
electrochemical sensors (electrodes)
Bacterial rhodopsins and their potential use in biotechnology
No full textHalobacteria sense and transduce light energy with four retinal proteins
occurring in their cell membrane. Bacteriorhodopsin is a light-driven proton
pump and mediates photosynthetic growth of the cells. Halorhodopsin is a
light-driven chloride pump and acts as an accessory pigment for net salt
uptake during growth. Sensory rhodopsin and phoborhodopsin (P4gq mediate
attraction to green light and repulsion by blue light via a signal chain
regulating the flagellar motor response and allow the cell to find optimal
environment for photosynthesis.
Main emphasis will be put on the description of the molecular properties of
the retinal proteins and the signal chain of the cell, but the potential use in
biotechnology will also be summarized. This includes solar energy conversion,
desalination, biosensors, light-triggered switches and optical storage
GAS DETECTION BY MEANS OF ENZYME-BASED GAS DETECTION TUBES
No full textRedox enzymes have been immobilized on polyacrylamide supports, packed into
detection tubes, and equilibrated with reactants allowing for the coupling of the
enzymic conversion of a gaseous substrate to a colour reaction. In preliminary experiments
it was shown that formaldehyde, carbon monoxide, and hydrogen peroxide
could be detected at concentrations in the range of the corresponding "MAK" values
SPECTROSCOPIC AND PHENOMENOLOGICAL CHARACTERIZATION OF BIOCHEMICALLY ACTIVE INTERFACES
No full textWe started to apply new analytical techniques of surface physics
to investigate prototypes of biochemically active interfaces both,
spectroscopically and phenomenologically.
A variety of different experimental tools of surface and interface
analysis is now available, which are in use in our laboratories /1/
and listed in the following. Their application makes possible to
determine quantum structures of interface
BIOSENSORS, AN INTERESTING SUBJECT FOR A CHEMICAL COMPANY ?
No full textBiosensors are a scientific and an economic subject. Interesting
applications are process control in biotechnology and diagnosis
in medicine. Requirements of the potential customer and the
structures of the corresponding markets are indicated
ENZYMATISCHE MODIFIZIERUNG VON ENZYMEN GLUCOAMYLASE ALS BEISPIEL AUS DER STÄRKEVERARBEITUNG
No full textThe chemical modification of microbial enzymes has gained increased
importance. A controlled enzymatic treatment of biocatalysts can be
another step towards "taylor-made" enzymes for use in food industry.
The transformation of starch containing raw materials in maltose, glucose
and fructose are established processes. Anyhow, it will be shown
in this presentation, how a specific modification of ASPERGILLUS
NIGER-Glucoamylases can lead to interesting properties in the application
of industrial saccharification.
During the late stage of the submerse production of glucoamylase from
ASPERGILLUS NIGER, a proteolytic modification of the enzyme molecule
happens. The formed enzyme shows a slightly different substrate specificity
than the original enzyme. The properties of the purified glucoamylase-
isoenzymes are demonstrated by means of degradation trials
with branched and linear oligosaccharides. Isomaltose is formed as the
main product of the reverse action from glucose as substrate by both
isoenzymes. Both glucoamylases are able to split alpha-1-6-glucosidic
bonds of maltooligosaccharides. The practical importance and possible
influences of a certain isoenzyme ratio of commercial glucoamylases
are explained with comparative saccharification trials using enzymatically
liquefied wheat starch as substrate
Title - Preface - Contents - List of authors
No full textIn 1982 Winter, Fersht and co-workers published their first report on the successful use
of site directed mutagenesis in protein engineering. Since then protein design (a more
rational variation of protein engineering) has been recognized as a promising and fascinating
field of research in many countries. In Japan and the U.S.A. researchinstitutes
have been founded to focus work on protein design. A growing number of other research
institutes in the United States, Canada, Japan and Europe haveinitiated broad
research projects on protein design. Prospects for the application of proteins with new,
designed functions or structures are very high in areas as diverse as pharmacology,
waste treatment, chemical synthesis, vaccine design, biosensors, in the food industry
etc. This concept wasclearly outlined in an excellent article by Ulmer in 1983 who on this
occasion coinedthe term ‘protein engineering’.
Research projects in protein design require a closecollaboration between specialists in
protein isolation and purification, in fermentation, in genetic engineering, protein crystallography
and modelling. This interdisciplinary approach involving protein chemists,
molecular biologists and structural chemists is essential for the completion of the protein
design cycle which, starting from a known protein, involves gene cloning and expression,
investigation of the properties and structure of the new protein and design of
new variants.
The present book evolved from a workshopheld at the GBF in Braunschweig in September
1988with the aim of bringing together a set of leading scientists and also some
initiates, in order to exchange viewsand ideas in protein design with special emphasis
on the following topics
— Methods andtheoretical concepts
— Protein design with (industrial) enzymes
— Protein design with biological response modifiers, including antibodies and protease
inhibitors.
Thus the book reflects the individual blendof activities of the workshop participants,
with no attempt to make a comprehensive review ofthis rapidly growing researchfield.
Wethank the GBF administration, especially M. Kramer and B. Zimmermann, for their
help in running the workshop. Our special thanks go to the speakers and chairpersons,
and the contributorsto this book