Hydrolysis of lactose solutions and wheys by whole cells of Kluyveromyces bulgaricus

1985 ◽  
Vol 21-21 (1-2) ◽  
pp. 103-107 ◽  
Author(s):  
M. Decleire ◽  
N. van Huyhn ◽  
J. C. Motte
Keyword(s):  
Whole Cells ◽  
Hydrolysis Of

Characterization of Muscle Sarcoplasmic and Myofibrillar Protein Hydrolysis Caused by Lactobacillus plantarum

1999 ◽  
Vol 65 (8) ◽  
pp. 3540-3546 ◽  
Author(s):  
Silvina Fadda ◽  
Yolanda Sanz ◽  
Graciela Vignolo ◽  
M.-Concepción Aristoy ◽  
Guillermo Oliver ◽  
...  
Keyword(s):  
Lactobacillus Plantarum ◽  
Myofibrillar Protein ◽  
Myofibrillar Proteins ◽  
Muscle Proteins ◽  
Whole Cells ◽  
Sarcoplasmic Proteins ◽  
Cell Extracts ◽  
Hydrophobic Nature ◽  
Hydrolysis Of

ABSTRACT Strains of Lactobacillus plantarum originally isolated from sausages were screened for proteinase and aminopeptidase activities toward synthetic substrates; on the basis of that screening,L. plantarum CRL 681 was selected for further assays on muscle proteins. The activities of whole cells, cell extracts (CE), and a combination of both on sarcoplasmic and myofibrillar protein extracts were determined by protein, peptide, and free-amino-acid analyses. Proteinase from whole cells initiated the hydrolysis of sarcoplasmic proteins. The addition of CE intensified the proteolysis. Whole cells generated hydrophilic peptides from both sarcoplasmic and myofibrillar proteins. Other peptides of a hydrophobic nature resulted from the combination of whole cells and CE. The action of both enzymatic sources on myofibrillar proteins caused maximal increases in lysine, arginine, and leucine, while the action of those on sarcoplasmic proteins mainly released alanine. In general, pronounced hydrolysis of muscle proteins required enzyme activities from whole cells in addition to those supplied by CE.

Dipeptide utilization by starter streptococci

1977 ◽  
Vol 44 (2) ◽  
pp. 309-317 ◽  
Author(s):  
B. A. Law
Keyword(s):  
Amino Acids ◽  
Transport System ◽  
Free Amino Acids ◽  
Free Amino ◽  
Essential Amino Acids ◽  
Exponential Phase ◽  
Whole Cells ◽  
Streptococcus Cremoris ◽  
Defined Media ◽  
Hydrolysis Of

SummaryOf 8 strains ofStreptococcus cremoristested, 5 grew almost as well in defined media in which various essential amino acids were supplied in dipeptides as they did in media containing the equivalent free amino acids. The remainder grew poorly or not at all in the peptide-containing media. Growth of peptide-utilizing strains was inhibited by also including structurally-related dipeptides in the medium, presumably due to competition for uptake by transport system carriers. Both types of starters produced cell-free dipeptidases recoverable from the medium of exponential phase cultures. Addition of the partly-purified extracellular dipeptidases to dipeptidecontaining test media initiated growth in strains unable to use peptides.Str. lactisgrew in defined peptide media, but the further addition of structurally-related dipeptides did not inhibit growth, either bcause each dipeptide was transported by a specific carrier or because peptides were hydrolysed extracellularly. The presence of cell-bound extracellular dipeptidase was indicated by the hydrolysis of dipeptides with washed whole cells in buffer. This was not observed withStr. cremorisstrains.

Characterization of lactococci and lactobacilli isolated from semihard goats' cheese

1991 ◽  
Vol 58 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Teresa Requena ◽  
Carmen Peláez ◽  
Michel J. Desmazeaud
Keyword(s):  
Leucine Aminopeptidase ◽  
Sodium Dodecyl ◽  
Skim Milk ◽  
Titratable Acidity ◽  
Aminopeptidase Activity ◽  
Whole Cells ◽  
Alanine Aminopeptidase ◽  
Triton X ◽  
Hydrolysis Of

SummarySeveral strains ofLactococcus lactissubsp.lactis, Lactobacillus caseiandLactobacillus plantarumisolated from traditional goats' cheese have been studied for titratable acidity, proteolysis in milk and enzymic activities. Aminopeptidasc activities were measured with whole cells and cells permeabilized with Triton X-100. Caseinolytic activity was investigated using electrophoresis in polyacrylamide gel with sodium dodecyl sulphate.Lc. lactissubsp.lactishad a level of proteolytic activity in skim milk greater than that ofLb. casei, while this activity inLb. plantarumwas very low. Alanine aminopeptidase activity was almost non-existent for all strains tested, while lysine aminopeptidase activity appeared to be of fundamentally intracellular origin. Leucine aminopeptidase activity was also greater in cells that had been permeabilized than in whole cells forLb. caseiandLb. plantarum. Lc. lactissubsp.lactisleucine aminopeptidase activity was greater in whole cells. No significant hydrolysis of casein was found withLb. caseiI FPL 725 andLb. plantarumIFPL 722 permeabilized with Triton X-100 after 24 h incubation with whole bovine casein.

Hydrolysis of β-casein (193-209) Fragment by Whole Cells and Fractions of Lactobacillus casei and Lactococcus lactis

1999 ◽  
Vol 64 (5) ◽  
pp. 899-902 ◽  
Author(s):  
L. Parra ◽  
P. Fernandez Palencia ◽  
V. Casal ◽  
T. Requena ◽  
C. Pelaez
Keyword(s):  
Lactococcus Lactis ◽  
Lactobacillus Casei ◽  
Whole Cells ◽  
Hydrolysis Of

scholarly journals Genetic Characterization of a Cell Envelope-Associated Proteinase from Lactobacillus helveticus CNRZ32

1999 ◽  
Vol 181 (15) ◽  
pp. 4592-4597 ◽  
Author(s):  
Jeffrey A. Pederson ◽  
Gerald J. Mileski ◽  
Bart C. Weimer ◽  
James L. Steele
Keyword(s):  
Cell Surface ◽  
Deletion Mutant ◽  
Cell Envelope ◽  
Physiological Role ◽  
Lactobacillus Helveticus ◽  
Whole Cells ◽  
A Cell ◽  
Hydrolysis Of

ABSTRACT A cell envelope-associated proteinase gene (prtH) was identified in Lactobacillus helveticus CNRZ32. TheprtH gene encodes a protein of 1,849 amino acids and with a predicted molecular mass of 204 kDa. The deduced amino acid sequence of the prtH product has significant identity (45%) to that of the lactococcal PrtP proteinases. Southern blot analysis indicates thatprtH is not broadly distributed within L. helveticus. A prtH deletion mutant of CNRZ32 was constructed to evaluate the physiological role of PrtH. PrtH is not required for rapid growth or fast acid production in milk by CNRZ32. Cell surface proteinase activity and specificity were determined by hydrolysis of αs1-casein fragment 1-23 by whole cells. A comparison of CNRZ32 and its prtH deletion mutant indicates that CNRZ32 has at least two cell surface proteinases that differ in substrate specificity.

scholarly journals A proton n.m.r. study of iminodipeptide transport and hydrolysis in the human erythrocyte. Possible physiological roles for the coupled system

1984 ◽  
Vol 220 (2) ◽  
pp. 553-560 ◽  
Author(s):  
G F King ◽  
P W Kuchel
Keyword(s):  
Concentration Dependence ◽  
Transport System ◽  
Human Erythrocytes ◽  
Whole Body ◽  
Differential Rate ◽  
Cell Water ◽  
Peptide Hydrolysis ◽  
Whole Cells ◽  
Progress Curve ◽  
Hydrolysis Of

The first description of a saturable iminodipeptide transport system present in human erythrocytes is given. The 1H-n.m.r. spectra of glycyl-L-proline and those of free glycine and L-proline are significantly different. This enabled the non-invasive monitoring by 1H-n.m.r. spectroscopy of the hydrolysis of the dipeptide in human erythrocytes and their lysates. The concentration-dependence of the rate of glycyl-L-proline hydrolysis by haemolysates was described by the Michaelis-Menten expression with Km = 14.1 +/- 2.4 mmol/litre and Vmax. = 130 +/- 10 mmol/h per litre of cell water. At concentrations of the dipeptide that saturated prolidase, hydrolysis of glycyl-L-proline by whole cells was approximately 130 times slower than by lysates. This rate difference indicated that transport is the rate-determining step in peptide hydrolysis by whole cells, and thus the concentration-dependence of the transport rate was determined. The membrane transport system was found to be saturable and could be described by the Michaelis-Menten expression with Kt = 4.7 +/- 0.4 mmol/litre and Vmax. = 0.997 +/- 0.026 mmol/h per litre of cell water. Numerical integration of a consistent set of differential rate equations that described a minimal model of the coupled transport-hydrolysis system successfully described prolonged time courses of peptide hydrolysis by whole cells. The simulations showed very low steady-state levels of dipeptide in the erythrocyte and very small lag periods (less than 5 min) in the progress curve describing the appearance of free amino acid inside the cells. The rates of transport of glycyl-L-proline into erythrocytes and kidney proximal-tubular epithelium were compared and the possible importance of erythrocyte prolidase in whole-body prolyl-peptide turnover is discussed.

scholarly journals Thromboplastin (tissue factor) in plasma membranes of human monocytes

1985 ◽  
Vol 228 (3) ◽  
pp. 735-743 ◽  
Author(s):  
O Hetland ◽  
A B Brovold ◽  
R Holme ◽  
G Gaudernack ◽  
H Prydz
Keyword(s):  
Plasma Membrane ◽  
Phospholipase C ◽  
Peripheral Blood ◽  
Plasma Membranes ◽  
Human Peripheral Blood ◽  
Indirect Evidence ◽  
Blood Monocytes ◽  
Peripheral Blood Monocytes ◽  
Whole Cells ◽  
Hydrolysis Of

The synthesis of thromboplastin, a potent trigger of blood coagulation, can be induced in human peripheral blood monocytes. Indirect evidence suggests that newly synthesized thromboplastin becomes in part available on the cell surface. We have attempted to study the localization and availability of thromboplastin more directly by isolating plasma membranes from isolated human peripheral blood monocytes. The specific activities of the plasma membrane markers increased 16-22-fold in these preparations with a recovery of about 15%. The contamination by mitochondria, lysosomes, nuclei and endoplasmic reticulum was low as estimated by marker enzymes and electron microscopy. In both unstimulated and stimulated monocytes thromboplastin was largely recovered in this plasma membrane fraction, providing direct evidence for its membrane localization. Phospholipase C (E.C. 3.1.4.3) is a potent inactivator of thromboplastin through its hydrolysis of the phospholipids necessary for thromboplastin activity [Otnaess, Prydz, Bjørklid & Berre (1972) Eur. J. Biochem. 27, 238-243]. About 70% of the total membrane thromboplastin activity was inactivated when whole cells were treated with phospholipase C and the membranes subsequently isolated. Following stimulation to induce thromboplastin synthesis, the plasma membranes showed a shift in their relative content of phosphatidylcholine and phosphatidylethanolamine consistent with a transmethylation process.

scholarly journals Characterization of β-galactosidase and α-galactosidase activities from the halophilic bacterium Gracilibacillus dipsosauri

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Charles E. Deutch ◽  
Amy M. Farden ◽  
Emily S. DiCesare
Keyword(s):  
Gel Filtration ◽  
Halophilic Bacterium ◽  
Peptide Sequencing ◽  
Exchange Chromatography ◽  
Galactosidase Activity ◽  
Ph Optimum ◽  
Whole Cells ◽  
Cell Extracts ◽  
Genes Encoding ◽  
Hydrolysis Of

Abstract Purpose Gracilibacillus dipsosauri strain DD1 is a salt-tolerant Gram-positive bacterium that can hydrolyze the synthetic substrates o-nitrophenyl-β-d-galactopyranoside (β-ONP-galactose) and p-nitrophenyl-α-d-galactopyranoside (α-PNP-galactose). The goals of this project were to characterize the enzymes responsible for these activities and to identify the genes encoding them. Methods G. dipsosauri strain DD1 was grown in tryptic soy broth containing various carbohydrates at 37 °C with aeration. Enzyme activities in cell extracts and whole cells were measured colorimetrically by hydrolysis of synthetic substrates containing nitrophenyl moieties. Two enzymes with β-galactosidase activity and one with α-galactosidase activity were partially purified by ammonium sulfate fractionation, ion-exchange chromatography, and gel-filtration chromatography from G. dipsosauri. Coomassie Blue-stained bands corresponding to each activity were excised from nondenaturing polyacrylamide gels and subjected to peptide sequencing after trypsin digestion and HPLC/MS analysis. Result Formation of β-galactosidase and α-galactosidase activities was repressed by d-glucose and not induced by lactose or d-melibiose. β-Galactosidase I had hydrolytic and transgalactosylation activity with lactose as the substrate but β-galactosidase II showed no activity towards lactose. The α-galactosidase had hydrolytic and transgalactosylation activity with d-melibiose but not with d-raffinose. β-Galactosidase I had a lower Km with β-ONP-galactose as the substrate (0.693 mmol l−1) than β-galactosidase II (1.662 mmol l−1), was active at more alkaline pH, and was inhibited by the product d-galactose. β-Galactosidase II was active at more acidic pH, was partially inhibited by ammonium salts, and showed higher activity with α-PNP-arabinose as a substrate. The α-galactosidase had a low Km with α-PNP-galactose as the substrate (0.338 mmol l−1), a pH optimum of about 7, and was inhibited by chloride-containing salts. β-Galactosidase I activity was found to be due to the protein A0A317L6F0 (encoded by gene DLJ74_04930), β-galactosidase II activity to the protein A0A317KZG3 (encoded by gene DLJ74_12640), and the α-galactosidase activity to the protein A0A317KU47 (encoded by gene DLJ74_17745). Conclusions G. dipsosauri forms three intracellular enzymes with different physiological properties which are responsible for the hydrolysis of β-ONP-galactose and α-PNP-galactose. BLAST analysis indicated that similar β-galactosidases may be formed by G. ureilyticus, G. orientalis, and G. kekensis and similar α-galactosidases by these bacteria and G. halophilus.

scholarly journals Double labeling with [3H]thymidine and [125I]iododeoxyuridine as a method for determining the fate of injected DNA and cells in vivo.

1975 ◽  
Vol 67 (2) ◽  
pp. 484-488 ◽  
Author(s):  
D K Myers ◽  
L E Feinendegen
Keyword(s):  
T Cells ◽  
Human Kidney ◽  
Enzymic Hydrolysis ◽  
Double Labeling ◽  
Exogenous Dna ◽  
Mouse Thymus ◽  
Whole Cells ◽  
Thymus Cells ◽  
Hydrolysis Of

Mice were injected intravenously and intraperitoneally with preparations of intestinal nucleoprotein, spleen nuclei, mouse thymus cells, or human kidney T cells whose DNA had been labeled with both [3H]thymidine (TdR) and [125I]-iododeoxyuridine (IUdR). Since free TdR is reutilized more efficiently than free IUdR produced by enzymic hydrolysis of the exogenous DNA, the ratio of [3H]TdR/[125I]IUdR in the DNA fraction of the tissues of the recipient mice provides a measure of the amount of intact exogenous DNA in the tissue. In most instances, the doubly labeled exogenous DNA was almost completely hydrolyzed within 1 day injection, but survival of the DNA from whole cells could be demonstrated in some cases.

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