scholarly journals Hydrolysis of κ-casein in solution by chymosin, plasmin, trypsin and Lactobacillus -proteinases

1993 ◽  
Vol 2 (6) ◽  
pp. 489-496 ◽  
Author(s):  
Anne Pihlanto-Leppälä ◽  
Eero Pahkala ◽  
Veijo Antila
Keyword(s):  
Proteolytic Activity ◽  
Lactobacillus Casei ◽  
Terminal Region ◽  
Lactobacillus Helveticus ◽  
Cell Free Extract ◽  
Enzyme Substrate ◽  
A Cell ◽  
Substrate Ratio ◽  
Almost All ◽  
Hydrolysis Of

The aim of this study was to examine the enzymatic hydrolysis of κ-casein by isolating and identifying the released peptides. The enzymes employed in the study were chymosin, plasmin and trypsin, as well as a cell-free extract from three Lactobacillus helveticus and nine Lactobacillus casei strains. The findings showed that the bond most sensitive to the proteolytic activity of chymosin was the Phe 105-Met 106. After 24 hours of hydrolysis a few other bonds in the casein macropeptide were also cleaved. Plasmin was found to have weak proteolytic activity under the conditions of this study. When the enzyme-substrate ratio was raised from 1:200 to 1:50, a few peptides were released from the N-terminal region. Trypsin was found to hydrolyze several κ-casein bonds, and peptides were released from almost all regions of the protein. The proteases of Lactobacillus had less effect than chymosin, plasmin or trypsin. The strains could be divided into three categories. L. helveticus strains had activity on bonds in the mid-section and C-terminal region, L. casei strains EB, P3, P8 and A 1 had activity on bonds in the N- and C-terminal regions, while L. casei A5 and M9 had activity only on bonds in the C-terminal region.

scholarly journals Hydrolysis of αs2-casein in solution by chymosin, plasmin, trypsin and Lactobacillus-proteinases

1993 ◽  
Vol 2 (2) ◽  
pp. 133-139
Author(s):  
Anne Pihlanto-Leppälä ◽  
Eero Pahkala ◽  
Minna Kahala ◽  
Veijo Antila
Keyword(s):  
Proteolytic Activity ◽  
Lactobacillus Helveticus ◽  
The Other ◽  
Cell Free Extract ◽  
Enzymic Hydrolysis ◽  
The Third ◽  
Other Hand ◽  
Almost All ◽  
Hydrolysis Of

The aim of this study was to examine the enzymic hydrolysis of αs2-casein by isolating and identifying the released peptides. The enzymes applied in the study were chymosin, plasmin and trypsin as well as cell free extracts from three strains of Lactobacillus helveticus and nine strains of L. casei. The findings showed that chymosin had weak proteolytic activity on αs2-casein. Plasmin, on the other hand, released numerous peptides under the used conditions. The majority of the identified fragments were released from the C terminal end of the substrate. Plasmin hydrolysed mainly Lys-X bonds. The third enzyme, trypsin, hydrolysed several bonds of αs2-casein. Peptides were released from almost all regions of the protein. Trypsin acted on the carboxyl sides of arginyl and lysyl residues. Cell free extract of lactobacilli had little activity on αs2-casein.

Evidence for cellular control in the synthesis of acetoin or α-ketoisovaleric acid by microorganisms

1974 ◽  
Vol 20 (6) ◽  
pp. 805-811 ◽  
Author(s):  
E. B. Collins ◽  
R. A. Speckman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Steady State ◽  
Serratia Marcescens ◽  
Lactobacillus Casei ◽  
Optically Active ◽  
Cell Free Extract ◽  
Data Support ◽  
A Cell ◽  
Cellular Control ◽  
Spent Media

Commercial α-acetolactate at pH 4.5 decarboxylated nonenzymatically (5 to 8%/h) to acetoin (69%) and diacetyl (31%), and an extract of Streptococcus diacetilactis 18-16 produced α-acetolactate (in addition to acetoin and diacetyl) from pyruvate in the presence of TPP and MgSO4. Nevertheless, α-acetolactate was not dispersed into media by any of four microorganisms (S. diacetilactis, strains 18-16 and DRC1, Saccharomyces cerevisiae 299, and Lactobacillus casei 393) that produced diacetyl and acetoin or by one (Serratia marcescens) that produced only acetoin. Lactobacillus casei and S. diacetilactis 18-16 produced unknown compounds that falsely indicated the presence of α-acetolactate when tests were made without separating acetoin and diacetyl from other components of the spent media. The production of acetoin by S. diacetilactis 18-16 was not inhibited by valine, the acetoin produced by this organism was optically active (+101.0°), and a cell-free extract of S. marcescens did not produce diacetyl while producing a large amount of acetoin. Data support the conclusion that the conversion of pyruvate to acetoin by some microorganisms and to α-ketoisovaleric acid by others is enzymatic and under cellular control, resulting in the synthesis of only steady-state amounts of enzymatically bound α-acetolactate in each of the pathways.

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.

Fructooligosaccharide Utilization by Salmonellae† and Potential Direct-Fed-Microbial Bacteria for Poultry

1995 ◽  
Vol 58 (11) ◽  
pp. 1192-1196 ◽  
Author(s):  
OMAR A. OYARZABAL ◽  
DONALD E. CONNER ◽  
WILLARD T. BLEVINS
Keyword(s):  
Cell Free Extract ◽  
Salmonella Spp ◽  
Fermentation Rate ◽  
Ph Values ◽  
Free Glucose ◽  
A Cell ◽  
The Media ◽  
Hydrolysis Of ◽  
Ferment Glucose ◽  
Measuring Ph

Experiments were done to characterize potential direct-fed-microbial (DFM) bacteria for poultry and Salmonella spp. with respect to their abilities to metabolize fructooligosaccharide substrates (FOS-50® or pure FOS). Oxygen uptake (QO2) by these bacteria in media containing either glucose, FOS-50®, or FOS was determined with a Warburg respirometer. QO2 values for Salmonella spp. In media containing glucose or FOS-50® were similar(P >0.05); however, QO2 values in medium with FOS were significantly lower (P <0.05).The QO2 values for Enterococcus faecium, Lactococcus lactis, and Pediococcus sp. were considerably lower, reflecting the inability of these bacteria to oxidatively utilize these carbohydrates. The ability of E. faecium, L. lactis, and Pediococcus sp. to ferment glucose, FOS-50®, or FOS was determined by measuring pH changes of the media. All carbohydrate sources were fermented by these bacteria, but at different rates. The lowest pH values (<4.6) were obtained in inoculated media supplemented with glucose. The highest fermentation rate was achieved by Pediococcus sp. (pH< 5.2 at 7h), while L. lactis showed the slowest fermentation rate (pH > 6.4 at 10 h). To test the ability of Pediococcus sp. to hydrolyze FOS substrates, a cell-free extract was spectrophotometrically analyzed for the presence of active enzymes capable of hydrolyzing FOS or sucrose (a component of FOS). Hydrolysis of FOS (release of glucose) but not of sucrose was evident. However, equal activity was found in aqueous FOS without the cell-free extract, which suggests that free glucose was a component of the FOS solution tested.

scholarly journals Enzyme-Catalyzed Production of Potato Galactan-Oligosaccharides and Its Optimization by Response Surface Methodology

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1465 ◽  
Author(s):  
Mirian Angelene González-Ayón ◽  
Ángel Licea-Claveríe ◽  
José Benigno Valdez-Torres ◽  
Lorenzo A. Picos-Corrales ◽  
Rosabel Vélez-de la Rocha ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Degree Of Polymerization ◽  
Enzyme Substrate ◽  
Low Degree ◽  
Ft Ir ◽  
Cellvibrio Japonicus ◽  
Substrate Ratio ◽  
Optimized Conditions ◽  
Hydrolysis Of

This work shows an optimized enzymatic hydrolysis of high molecular weight potato galactan yielding pectic galactan-oligosaccharides (PGOs), where endo-β-1,4-galactanase (galactanase) from Cellvibrio japonicus and Clostridium thermocellum was used. For this, response surface methodology (RSM) by central composite design (CCD) was applied. The parameters varied were temperature (°C), pH, incubation time (min), and enzyme/substrate ratio (U/mg). The optimized conditions for the production of low degree of polymerization (DP) PGOs were obtained for each enzyme by spectrophotometric assay and confirmed by chromatography. The optimal conditions predicted for the use of C. japonicus galactanase to obtain PGOs of DP = 2 were T = 51.8 °C, pH 5, E/S = 0.508 U/mg, and t = 77.5 min. For DP = 3, they were T = 21 °C, pH 9, E/S = 0.484 U/mg, and t = 12.5 min; and for DP = 4, they were T = 21 °C, pH 5, E/S = 0.462 U/mg, and t = 12.5 min. The efficiency results were 51.3% for substrate hydrolysis. C. thermocellum galactanase had a lower yield (35.7%) and optimized conditions predicted for PGOs of DP = 2 were T = 60 °C, pH 5, E/S = 0.525 U/mg, and time = 148 min; DP = 3 were T = 59.7 °C, pH 5, E/S = 0.506 U/mg, and time = 12.5 min; and DP = 4, were T = 34.5 °C, pH 11, E/S = 0.525 U/mg, and time = 222.5 min. Fourier transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) characterizations of PGOs are presented.

Influence of process variables on the hydrolysis of shark muscle protein / Influencia de las variables de proceso en la hidrólisis de proteína del músculo de tiburón

1998 ◽  
Vol 4 (2) ◽  
pp. 91-98 ◽  
Author(s):  
F. Mendonça Diniz ◽  
A.M. Martin
Keyword(s):  
Muscle Protein ◽  
Squalus Acanthias ◽  
Degree Of Hydrolysis ◽  
Soluble Nitrogen ◽  
Process Variables ◽  
Optimum Conditions ◽  
Enzyme Substrate ◽  
Wet Weight ◽  
Substrate Ratio ◽  
Hydrolysis Of

Muscle tissue from the spiny dogfish ( Squalus acanthias) was enzymatically hydrolysed using a bacterial endopeptidase. The influence of the process variables (temperature, pH, enzyme/ substrate ratio and reaction time) was investigated with regards to the extent of proteolytic degra dation and the recovery of soluble nitrogen from the substrate. Maximum significant nitrogen recovery (NR) was found to be 76.2%, in a 2 h proteolytic reaction. Optimum conditions were 55 °C, pH 8.0 and an enzyme/substrate ratio of 40 mg enzyme/g minced shark muscle (wet weight basis). Under these conditions, a degree of hydrolysis (DH) of 18.6% was obtained. A linear corre lation ( R2 = 0.99) was found to exist between the two measured parameters, NR and DH.

Optimization of the Enzymatic Hydrolysis of Tilapia Frames

2012 ◽  
Vol 554-556 ◽  
pp. 1387-1394
Author(s):  
He Jian Xiong ◽  
Longfei Cao ◽  
Huajun You ◽  
Qingpi Yan ◽  
Ying Ma
Keyword(s):  
Amino Acids ◽  
Enzymatic Hydrolysis ◽  
Free Amino Acids ◽  
Free Amino ◽  
Protein Supplementation ◽  
Degree Of Hydrolysis ◽  
Enzyme Substrate ◽  
Initial Ph ◽  
Substrate Ratio ◽  
Hydrolysis Of

Tilapia frames were subjected to enzymatic hydrolysis using Flavouzryme and Papain with a ratio of 2:1. The relationship of temperature (40 to 60°C), enzyme: substrate ratio (0.5% to 4.5%), initial pH (6.0 to 8.0) and hydrolysis time (1h to 9h) to the degree of hydrolysis were determined. The enzymatic hydrolysis was optimized for maximum degree of hydrolysis using surface response methodology. The optimum conditions for enzymatic hydrolysis of tilapia frames were temperature 53°C, enzyme : substrate ratio of 3.5%, initial pH 7.2, and reaction time 7h. Under these conditions a degree of hydrolysis of 40.01% were obtained. The yield of free amino acids in the hydrolysate was 46.61mg/g tilapia frames. The flavor amino acids and essential amino acids occupied up to 31.8% and 49.0% of the total free amino acids respectively. The hydrolysate of waste tilapia frames showed good potential for applications such as protein supplementation in food system.

Artificial neuronal networks (ANN) to model the hydrolysis of goat milk protein by subtilisin and trypsin

2018 ◽  
Vol 85 (3) ◽  
pp. 339-346 ◽  
Author(s):  
Francisco Javier Espejo-Carpio ◽  
Raúl Pérez-Gálvez ◽  
Antonio Guadix ◽  
Emilia María Guadix
Keyword(s):  
Milk Protein ◽  
Binding Capacity ◽  
Goat Milk ◽  
Degree Of Hydrolysis ◽  
Enzymatic Reactions ◽  
Water Binding ◽  
Enzyme Substrate ◽  
Ann Models ◽  
Substrate Ratio ◽  
Hydrolysis Of

The enzymatic hydrolysis of milk proteins yield final products with improved properties and reduced allergenicity. The degree of hydrolysis (DH) influences both technological (e.g., solubility, water binding capacity) and biological (e.g., angiotensin-converting enzyme (ACE) inhibition, antioxidation) properties of the resulting hydrolysate. Phenomenological models are unable to reproduce the complexity of enzymatic reactions in dairy systems. However, empirical approaches offer high predictability and can be easily transposed to different substrates and enzymes. In this work, the DH of goat milk protein by subtilisin and trypsin was modelled by feedforward artificial neural networks (ANN). To this end, we produced a set of protein hydrolysates, employing various reaction temperatures and enzyme/substrate ratios, based on an experimental design. The time evolution of the DH was monitored and processed to generate the ANN models. Extensive hydrolysis is desirable because a high DH enhances some bioactivities in the final hydrolysate, such as antioxidant or antihypertensive. The optimization of both ANN models led to a maximal DH of 23·47% at 56·4 °C and enzyme–substrate ratio of 5% for subtilisin, while hydrolysis with trypsin reached a maximum of 21·3% at 35 °C and an enzyme–substrate ratio of 4%.

scholarly journals Enzymatic hydrolysis of wheat starch for glucose syrup production

DYNA ◽  
2020 ◽  
Vol 87 (214) ◽  
pp. 173-182
Author(s):  
Juan Camilo Acosta Pavas ◽  
Laura Alzate Blandón ◽  
Ángela Adriana Ruiz Colorado
Keyword(s):  
Enzymatic Hydrolysis ◽  
Reaction Times ◽  
Wheat Starch ◽  
Inhibitory Effects ◽  
Enzyme Substrate ◽  
Glucose Syrup ◽  
Substrate Ratio ◽  
Hydrolysis Of

An analysis of the enzymatic hydrolysis of wheat starch was performed. The gelatinization stage was carried out between 90-95°C for 15min. In the liquefaction stage, a commercial α-amylase was used with an enzyme-substrate ratio (E/S ratio) 0.036%w/w at 60°C and pH 5.8 for 4h. In the saccharification stage, a commercial amyloglucosidase was used with an E/S ratio of 0.11% w/w at 60°C and pH 4.3 for 6h. A second hydrolysis was evaluated using a E/S ratio of  0.18%w/w in the saccharification stage. Two methods of enzymatic deactivation, boiling temperatures and pH were evaluated. Inhibitory effects were studied by adding 180g/L of glucose to the process. It is concluded that increases in the E/S ratio decrease reaction times but reaches similar concentrations than lower ratios, the most efficient enzymatic deactivation method is pH. In the inhibition tests, it was determined that there are no glucose inhibitory effects.

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