University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Maria-Regina Kula

Abbrev:
Kula, M.R.
Other Names:
Address:
Institute of Enzyme Technology, Heinrich Heine University Düsseldorf, P.O. Box 20 50, D(W)-5170 Jülich Germany
Phone:
NA
Fax:
NA
Email:

Citations 7

"Monitoring Of Enzymes During Chromatographic Separations"
J. Biotechnol. 1990 Volume 14, Issue 1 Pages 99-114
Wolfgang W. Stamm and Maria-Regina Kula*

Abstract: An online enzyme assay is presented based on flow injection techniques combined with fluorimetric detection. It allows to monitor NAD-dependent oxidoreductases during the purification of microbial crude extracts or partially purified enzymes by fast protein liquid chromatography (FPLC) in a near real-time mode. The arrangement is simple and can be easily integrated in the chromatographic system avoiding dead volumes. A high measuring frequency (up to 180 samples h-1) and a short response time (10-30 s) are achieved. The method has a low limit of detection (approximately 0.01 U mL-1), and a good reproducibility (1-4%), the injected sample volume is only 2 µL. Microbial alanine dehydrogenase, phenylalanine dehydrogenase and formate dehydrogenase were purified using fast protein liquid chromatography (Pharmacia LKB). Eluates passed through a UV detector then flow injection analysis (FIA) valve (Cheminert U Auto CSV-2) before collecting as fractions. At timed intervals 2 µL of sample was injected into the reagent mixture composed of buffer solution, substrate, and NAD coenzyme. The resulting NADH was estimated in the flow cell of an HPLC fluorescence detector at 460 nm (excitation at 340 nm). Sample throughput was 180 h-1, the limit of detection was 0.007 to 0.1 U mL-1 and the coefficient of variation (n = 13) was 1.0 to 1.4%.
Enzymes HPLC Fluorescence Enzyme Detection limit Detector Flowcell

"Online Measurement Of Extracellular Proteins In The Continuous Cellulase Production By Flow Injection Analysis"
Enzyme Microb. Technol. 1989 Volume 11, Issue 2 Pages 96-105
Wolfgang W. Stamm, Gunnar Pommerening, Christian Wandrey and Maria-Regina Kula

Abstract: The BCA protein assay was adapted to flow injection analysis to monitor the production of extracellular cellulases of Trichoderma species in batch and continuously operated fermentations. Response of the assay to protein (bovine serum albumin) was linear in the range of 0.1-2.0 g L-1; standard deviation of the calibration graph was 0.86%, accuracy and standard deviation were < +1.5% and 0.9% in the upper range, < +8% and < 2% in the lower range, respectively. Interferences from technical fermentation media were taken into consideration and can be calculated. The slow fermentation process was measured with a frequency of 0.5 samples h-1 over a period of 380 h. In each measuring cycle, recalibration was carried out. The necessary cell-free sample stream for the analytical system was obtained by installing the BIOPEMR, a steam-sterilizable sampling device which showed excellent performance even for long-term fermentations; membranes had to be changed after about 10 days only to keep the protein transmission constant (60-95%, depending on the special protein).
Proteins Albumin Cow Serum Enzyme Tecator

"Online Monitoring Of Enzymes In Downstream Processing By Flow Injection Analysis"
Enzyme Microb. Technol. 1985 Volume 7, Issue 12 Pages 607-612
Achim Recktenwald, Karl-Heinz Kroner and Maria-Regina Kula

Abstract: A Tecator flow injection analysis-5020 analyzer. was coupled to a spectrophotometer and fitted with a temperature control device (deviation <0.1°C) and a laboratory-built sampling device with a Millipore 0.45 µm membrane. The equipment was used in assays for formate dehydrogenase and leucine dehydrogenase in process control of enzyme-production processes. Both assays involved the formation of NADH and absorbance measurement at 340 nm; modifications necessary for the flow injection implementation are described. Calibration graphs for both enzymes were almost rectilinear up to ~11 iu mL-1.
Enzymes Enzyme, formate dehydrogenase Enzyme, leucine dehydrogenase Spectrophotometry Membrane Process control Tecator Millipore

"Rapid Online Protein Detection In Biotechnological Processes By Flow Injection Analysis"
Enzyme Microb. Technol. 1985 Volume 7, Issue 4 Pages 146-149
Achim Recktenwald, Karl-Heinz Kroner and Maria-Regina Kula

Abstract: Two rapid methods for on-line protein determination useful for control purposes in the automation of biotechnological processes such as fermentation and downstream processing are described. Both methods are derived from colorimetric laboratory biuret and Bradford protein assays adapted to a flow injection analyzer..
Protein Spectrophotometry Tecator

"Process Control In Enzyme Production And Purification By Online Dialysis"
Biotech Forum 1985 Volume 2, Issue 1 Pages 56-57
Husted, H.;Kroner, K.H.;Kula, M.R.

Abstract: NA
Enzymes Dialysis Enzyme Process control

"Determination Of L-glutamate And L-glutamine By Flow Injection Analysis And Chemiluminescence Detection: Comparison Of An Enzyme Column And Enzyme Membrane Sensor"
Anal. Chim. Acta 1993 Volume 271, Issue 2 Pages 231-237
Gert Blankenstein, Frank Preuschoff, Uwe Spohn and Karl-Heinz Mohr, Maria-Regina Kula*

Abstract: L-Glutamate and L-glutamine were determined by luminol chemiluminescence with flow injection analysis. Glutamate oxidase and glutaminase were co-immobilized on controlled-poreglass (CPG) for the determination of glutamate and glutamine. The hydrogen peroxide produced by enzymatic degradation was detected by luminol chemiluminescence catalyzed by peroxidase either immobilized on CPG or on a pre-activated membrane. Arthromyces ramosus peroxidase produced a much stronger luminescence signal than horseradish peroxidase. Immobilization of the microbial peroxidase on a membrane inside the flow cell simplified the technique. The membrane sensor had a detection limit of 0.1 µM-L-glutamate and 1 µM-L-glutamine. The calibration graph was rectilinear for 0.1 to 60 µM-L-glutamate and 1 µM to 2.5 mM L-glutamine.
l-Glutamate l-Glutamine Chemiluminescence Sensor Column Immobilized enzyme Membrane Controlled pore glass

"Cell Permeabilization As A Tool For Measurement Of Intra-cellular Enzyme Activity In A Flow Injection System"
Anal. Chim. Acta 1991 Volume 248, Issue 2 Pages 371-378
Gert Blankenstein and Maria-Regina Kula

Abstract: Yeast cells (Candida boidinii) were incubated at 50°C for 5 min with 75 mM potassium phosphate buffer (pH 7.5) containing 0.5% digitonin, 0.5% Triton X-100 and 100 mM EDTA. The mixture was subjected to flow injection analysis with mixing with carrier solution and reagent solution (cf. Recktenwald et al. Enzyme Microb. Technol.., 1985, 7, 607). The mixture was subjected to dialysis and the NADH was detected fluorimetrically at 460 nm (excitation at 340 nm). The calibration graph was rectilinear for 0.01 to 3.0 iu mL-1 of NAD-dependent formate dehydrogenase.
Fluorescence Permittivity Dialysis Enzyme Heated reaction Triton X Surfactant