Leszek Stepaniak

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An intracellular tributyrin esterase from Lactobacillus plantarum 2739 was purified to homogeneity by chromatography on DEAE cellulose, Sephacryl 200, carboxymethylcellulose, and Mono Q. The enzyme E2 was separated on DEAE cellulose from a second esterase, E1, and a minor esterase. Additional minor esterases were separated from E2 during chromatography on(More)
Proteolytic activities were investigated in sorghum-based togwa prepared by natural fermentation and using starter cultures previously isolated from the native product, i.e., Lactobacillus brevis, Lactobacillus cellobiosus, Lactobacillus fermentum, Lactobacillus plantarum, Pediococcus pentosaceus, and Issatchenkia orientalis in coculture with either L.(More)
After a brief description of the properties of bioactive peptides, the proteolytic activation of the bioactive sequences from milk protein precursors is discussed. The ability of proteolytic enzymes from various sources, especially from lactic acid bacteria, to release bioactive peptides and the physiological and biotechnological significance of these(More)
Aeration increased the growth and lipase production in milk by Pseudomonas fluorescens strain AFT 36, isolated from refrigerated bulk milk. A heat-stable lipase was isolated from a shaken milk culture of this microorganism by DEAE-chromatography and gel filtration in Sepharose 6B. The lipase-rich fraction from DEAE cellulose contained 3 lipases that were(More)
Different aminopeptidase and endopeptidase substrates were assessed for the detection of enzymatic activity of microorganisms collected from the surface of aerobically cold-stored pork and beef. The most sensitive substrates were fluorogenic Ala-7-amino-4-methylcoumarin (Ala-AMC) or Leu-AMC and colorogenic Ala-p-nitroanilide (Ala-pNA). Activity on natural(More)
Peptides from hydrolysates of fish proteins and from cheeses were analysed for inhibition of prolyl endopeptidase (PE) isolated from porcine muscle. Muscles of cod, salmon, and trout were homogenised and incubated at pH 4.0 with pepsin and then at pH 7.5 with trypsin to obtain fish protein hydrolysates. Homogenates were incubated without exogenous enzymes(More)
Pseudomonas strain AFT 21 produced three heat stable extracellular proteinases in milk and nutrient broth at 7 or 21 degrees C, but the proportions depended on medium and cultivation temperature. The three proteinases were EDTA- and o-phenanthroline-sensitive metalloenzymes and were not inhibited by N-ethylmaleimide or phosphoramidon. Proteinases I and II(More)
A metalloproteinase, isolated from a shaken milk culture of Pseudomonas fluorescens AFT 36 by chromatography in DEAE and CM-cellulose and Sephadex G-150, was very unstable in 0.1 M-phosphate buffer, pH 6.6, being completely denatured above 70 degrees C in 1 min. It was also unstable in a Ca-containing buffer (synthetic milk salts, SMS) between 50 and 60(More)
An intracellular oligopeptidase from Lactobacillus paracasei Lc-01 has been purified to homogeneity by Fast Flow Q Sepharose, hydroxyapatite, and Mono Q chromatography. The molecular mass of the enzyme was determined to be 140 kDa by gel filtration and approximately 30 kDa by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and SDS-capillary(More)
A dimeric, 90 kDa subunit intracellular proline iminopeptidase from Propionibacterium freudenreichii ATCC 9614 was purified to homogeneity by chromatography on hydroxyapatite, Sephacryl 200, Phenyl Superose and Mono Q. The enzyme was specific on Pro-p-nitroanilide and Pro-X dipeptides. It hydrolyzed 2 fragments of hormone oligopeptides with an N-terminal(More)