Analysis of trypsin activity at β-casein layers formed on hydrophobic surfaces using a multiharmonic acoustic method

The Analyst ◽  
2022 ◽  
Author(s):  
Sandro Spagnolo ◽  
Eric S. Muckley ◽  
Ilia N. Ivanov ◽  
Tibor Hianik
Keyword(s):  
Enzymatic Activity ◽  
Milk Proteins ◽  
Acoustic Method ◽  
Trypsin Activity ◽  
Hydrophobic Surfaces ◽  
Nutritional Characteristics

Proteolysis of milk proteins, such as caseins, caused by milk proteases, can change the organoleptic and nutritional characteristics of milk, and therefore it is essential to monitor this enzymatic activity....

Effects of Lyophilization and Use of Probiotics on Donkey's Milk Nutritional Characteristics

2011 ◽  
Vol 7 (5) ◽  
Author(s):  
Silvia Vincenzetti ◽  
Michele Savini ◽  
Cinzia Cecchini ◽  
Daniela Micozzi ◽  
Francesco Carpi ◽  
...  
Keyword(s):  
Milk Proteins ◽  
Storage Conditions ◽  
Limited Range ◽  
Raw Material ◽  
Cow Milk ◽  
Nutritional Properties ◽  
Fresh Milk ◽  
Nutritional Characteristics ◽  
Probiotic Strains ◽  
Ige Mediated

Cow milk protein allergy (CMPA) is an abnormal IgE-mediated reaction to cow milk proteins. Donkey’s milk could be considered suitable for feeding young children affected by severe IgE-mediated CMPA because its nutritional properties and composition are very close to human milk. Since donkey’s milk is available during a limited range of months during the year, it may be useful to find better storage conditions for this product. This study investigated the effects of the lyophilization treatment on donkey’s milk nutritional characteristics, and the results were compared with those obtained on fresh and frozen milk. Nutritional properties of lyophilized donkey’s milk remained basically unchanged compared with fresh milk. Two different probiotic strains were added to lyophilized donkey’s milk, and their viability was evaluated after milk reconstitution. The results obtained confirmed the possibility of producing a probiotic infant formula with beneficial properties using donkey’s milk as raw material.

Enzyme-forming function of the pancreas in persons with diseases of the stomach and duodenum

1982 ◽  
Vol 63 (3) ◽  
pp. 57-58
Author(s):  
L. K. Eremin
Keyword(s):  
Hydrochloric Acid ◽  
Acid Solution ◽  
Enzymatic Activity ◽  
Gastric Juice ◽  
Hydrochloric Acid Solution ◽  
Negative Pressure ◽  
Clinical Signs ◽  
Empty Stomach ◽  
Trypsin Activity ◽  
Jet Pump

The enzymatic activity of the pancreas was studied in persons with diseases of the stomach and duodenum without clinical signs of concomitant pancreatitis. The activity of amylase was determined by Wolgemuth, lipase in the blood - by the Comfort method, and in the duodenal contents - by the Bondi method modified by MS Rozhkova, trypsin activity - by the Fuld-Gross-Michaelis method. The contents of the duodenum were obtained for 20 minutes by a two-channel probe on an empty stomach and after the introduction of 30 ml of 0.5% hydrochloric acid solution with separate constant aspiration of it and gastric juice using a water-jet pump, creating a negative pressure within 7 kPa.

Immobilization of Protein on Silanized Orthopedic Biomaterials

1993 ◽  
Vol 331 ◽  
Author(s):  
D. A. Puleo
Keyword(s):  
Enzyme Activity ◽  
Enzymatic Activity ◽  
Surface Area ◽  
Free Amino ◽  
Guanidine Hydrochloride ◽  
Trypsin Activity ◽  
Amino Groups ◽  
Schiff’S Base ◽  
Surface Hydroxyl ◽  
Nominal Surface

AbstractWe have begun to examine methods for biochemically modifying orthopedic biomaterials by covalently immobilizing peptides, proteins, and enzymes. The surfaces of Co-Cr-Mo samples were first silanized using γ-aminopropyltriethoxysilane (APS), which interacts with surface hydroxyl moieties. Derivatization of biomaterial samples with solutions of APS in acetone produced a concentration-dependent number of reactive NH2 groups. The silane layers became unstable and were easily disrupted at concentrations above 2% APS. The enzyme, trypsin, was then coupled to the alkylamine-derivatized samples by formation of Schiff's base linkages via glutaraldehyde. Enzymatic activity of trypsin-conjugated Co-Cr-Mo samples was quantified by determining cleavage of the substrate BAEE. Both alkoxysilane-treated and untreated samples bound trypsin in an active state. When treated with 5 M guanidine hydrochloride to elute noncovalently bound protein, however, nearly all of the trypsin was removed from or rendered inactive on samples either not treated with APS or derivatized with low (<0.5%) concentrations. On the contrary, 1 and 2% APS-treated samples retained appreciable enzyme activity. Approximately 27 and 35% residual trypsin activity was measured on the 1 and 2% APSderivatized Co-Cr-Mo samples, respectively. Active trypsin remained immobilized on the APS-derivatized substrates when at least 35 free amino groups per nm2 of nominal surface area were available for protein coupling.

Fate of pancreatic enzymes during small intestinal aboral transit in humans

1986 ◽  
Vol 251 (4) ◽  
pp. G475-G480 ◽  
Author(s):  
P. Layer ◽  
V. L. Go ◽  
E. P. DiMagno
Keyword(s):  
Enzymatic Activity ◽  
Structural Integrity ◽  
Amylase Activity ◽  
Lipolytic Activity ◽  
Pancreatic Insufficiency ◽  
Exocrine Pancreatic Insufficiency ◽  
Pancreatic Enzymes ◽  
Trypsin Activity ◽  
Tryptic Activity ◽  
Small Intestinal

To determine survival of pancreatic enzymes during small intestinal aboral transit in humans, seven healthy volunteers were intubated with an oroileal tube. By using nonabsorbable markers we measured the cumulative amount of lipase, trypsin, and amylase activities and lipase and trypsin immunoreactivities delivered postprandially to the duodenum, midjejunum, and terminal ileum. We found that as the enzymes moved from duodenum to ileum, 74% of amylase activity, 22% of trypsin activity, and 1% of lipase activity survived transit. Enzymatic activity and immunoreactivity of trypsin and lipase disappeared at different rates, suggesting that for these enzymes the sites of enzymatic activity and immunorecognition are not identical. Since tryptic activity is present even in the absence of immunorecognizable trypsin, complete structural integrity of the trypsin molecule may not be essential for its enzymatic activity. The short intraluminal survival of lipolytic activity may partially explain why patients with progressive exocrine pancreatic insufficiency malabsorb fat earlier than other nutrients.

scholarly journals Adsorption of Milk Proteins (β-Casein and β-Lactoglobulin) and BSA onto Hydrophobic Surfaces

Materials ◽  
2017 ◽  
Vol 10 (8) ◽  
pp. 893 ◽  
Author(s):  
Leonor Pérez-Fuentes ◽  
Carlos Drummond ◽  
Jordi Faraudo ◽  
Delfi Bastos-González
Keyword(s):  
Milk Proteins ◽  
Hydrophobic Surfaces ◽  
Β Lactoglobulin

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

A Method for the Colorimetric Determination of β-Glucuronidase in Urine, Serum, Tissue; Assay of Enzymatic Activity in Health and Disease

1959 ◽  
Vol 36 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Julius A. Goldbarg ◽  
Esteban P. Pineda ◽  
Benjamin M. Banks ◽  
Alexander M. Rutenburg
Keyword(s):  
Enzymatic Activity ◽  
Colorimetric Determination ◽  
Health And Disease ◽  
Urine Serum
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