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At least 19 recordsLinked to original sources

PubMed1978

Four new methods of debittering protein hydrolysates and a fraction of hydrolysates with high content of essential amino acids.

Extraction of enzymatic protein hydrolysates with azeotropic secondary butyl alcohol (SBA) or aqueous ethanol (AE) or aqueous isopropranol (AI), seems to be an efficient and generally applicable method for removal of bitter compounds. The bitter peptides are concentrated in the alcohol-phase which has an extremely bitter taste. It has a concentration of 40-70 p. 100 essential amino-acids. In the alcohol-phase leucine, isoleucine, phenylalamine and tryptophan were particularly increased. Experiments showed that the bitterness of the alcohol-soluble fraction could be reduced by applying the plastein reaction. A reduction in bitterness of protein hydrolysates could also be achieved by applying hydrophobic interaction chromatography. Of tested gels, hexyl-sepharose was found to be the most effective for debittering of protein hydrolysates.

Amino Acids↗

PubMed2025

Physiological and metabolic responses of Zymomonas mobilis to lignocellulosic hydrolysate.

Zymomonas mobilis is a promising biocatalyst for the sustainable conversion of lignocellulosic sugars into biofuels and bioproducts, yet its response to lignocellulosic hydrolysates remains poorly understood. Here, we investigate the physiological response of Z. mobilis to ammonia fiber expansion (AFEX)-pretreated switchgrass hydrolysate using a systems-level approach integrating LC-MS/MS-based lipidomics and shotgun proteomics. Growth on hydrolysate induced substantial shifts in fatty acid and membrane phospholipid composition, alongside broad proteomic remodeling. Notably, Z. mobilis exhibited a stress response characterized by the upregulation of heat shock proteins and efflux transporters and the downregulation of cell motility proteins. Unexpectedly, hydrolysate exposure also led to a robust upregulation of the Entner-Doudoroff pathway, the ethanol fermentation pathway, and other central carbon metabolism enzymes, indicating a substantial cellular investment potentially driven by additional nutrient availability in hydrolysate. These findings provide new insights into the metabolic adaptations of Z. mobilis to lignocellulosic hydrolysates, informing strategies to enhance its biofuel production capabilities.IMPORTANCEBiomass pretreatment processes release fermentable sugars from lignocellulosic biomass, but they also generate inhibitors that can impact microbial metabolism. This study provides a systems-level evaluation of how Zymomonas mobilis responds to hydrolysate stress, revealing distinct physiological and lipid membrane remodeling responses. While some stress responses overlap with those induced by ethanol and isobutanol toxicity, both valuable biofuels, hydrolysate exposure elicits unique metabolic shifts. These findings offer valuable insights for engineering Z. mobilis strains with improved tolerance and performance for efficient bioconversion of lignocellulosic hydrolysates into biofuels and bioproducts.

Zymomonas↗

PubMed1979

Sodium acetate as a preservative in protein hydrolysate solutions.

The inhibitory effect of sodium acetate on microorganism growth in protein hydrolysate solutions was studied. Solutions of 5% protein hydrolysate and 5% dextrose in water (seven parts) and 50% dextose in water (three parts) containing 0, 30, 50 and 90 mEq/liter of sodium acetate were inoculated with Staphylococcus aureus, Escherichia coli, Candida albicans and Pseudomonas aeruginosa. The number of colony-forming units in the solutions after inoculation was compared with that after incubation for 24 hours at 37 C. Sodium acetate inhibited growth of S aureus and E coli. Growth of P aeruginosa was inhibited in protein hydrolysate solutions with and without sodium acetate; inhibition could not be attributed solely to sodium acetate and may have been releated to pH of the solutions (4.7 to 5.4). Growth of C albicans was not inhibited by sodium acetate. Sodium acetate reduced growth of some common contaminants of protein hydrolysates. Sodium acetate is known to reduce metabolic acidosis, a reported complication of parenteral nutrient therapy and a possible predisposing factor in C albicans sepsis. Addition of sodium acetate to protein hydrolysate solutions should be considered seriously.

Acetates↗

PubMedDate not supplied

[Effect of parenterally administered protein hydrolysates on the secretory function of the small intestine].

The effect of intravenous infusion of proteinic hydrolysates on the secretory function of the intestines was studied in dogs with an intestinal loop isolated starting from the initial portion of the jejunum. The preparation of proteinic hydrolysates, such as the caseine hydrolysate TSOLIPK, aminopeptide and hydrolysine L-103 with their drop-by-drop infusion into the posterior vena cava to dogs on an empty stomach were found to have in most cases an effect on the periodicity of the small intestine secretory activity. The infusion of proteinic hydrolyastes failed to exert any essential influence on the secretion of the dense proportion of the juice, whereas the secretion of the liquid component of the intestinal juice increased in all experiments involving introduction of all the proteinic hydrolysates. The concentration of the total protein in the liquid part of the intestinal juice with intravenous infusion of the preparations remained unchanged. At the same time, the amount of protein secreted together with the intestinal juice at the rate of single secretory action was in the instance of the caseine hydrolysate TSOLIPK and aminopeptide infusion proved 1 1/2--3 times as great as in the tests without infusion.

Animals↗

PubMed1976

Human skin proteases. Fractionation of psoriasis scale proteases and separation of a plasminogen activator and a histone hydrolysing protease.

Psoriatic scale proteases were found to be extracted effectively in salt solution (1 mol/l) containing Triton X-100 (5 g/l). The extraction in dilute buffer or sucrose yielded low activities. The acid (0.25 N H2SO4) and KSCN (2 mol/l) solutions effectively extracted plasminogen activator. Fibrinolysin was most active in salt (1 mol/l KCl) and in KSCN (2 mol/l) extracts. Psoriatic scale proteases were fractionated by Sephadex G-100 gel filtration and further by DEAE cellulose chromatography. Five different enzyme preparations were obtained. The first preparation, resembling cathepsin D, effectively hydrolysed hemoglobin at pH 3.5 and casein at pH 5.8 and was insensitive to protease modifiers. The second preparation effectively hydrolysed trypsin substrates (AGLME, TAME, BAEE and BANA) and also histone and casein at pH 7.2 and was inhibited by protease inhibitors, TLCK and E-600. The third preparation hydrolysed histone and casein at pH 10.2 and was effectively inhibited by E-600 and partially by protease inhibitors and TPCK. The fourth preparation, resembling cathepsin B1, hydrolysed BANA and BAEE at pH 5.8 and was activated by SH-reagents and EDTA. The fifth enzyme preparation hydrolysed ATEE and was inhibited by E-600 and TPCK. Plasminogen activator was found mainly in the second enzyme preparation and fibrinolysin activity in the third and fifth enzyme preparations. The second, third and fifth enzyme preparations were different from the enzymes found in healthy human skin. The proteases of psoriatic scale resemble those of tissue and cell cultures undergoing rapid cell division. The possible role of proteases in the increased cell division in psoriasis plaque is discussed.

Histones↗

PubMed1977

Intramolecular general base-catalyzed ester hydrolyses by the imidazolyl group.

Intramolecular general base catalysis by the imidazolyl group was found in the hydrolyses of endo-5-[4;(5')-imidazolyl]-bicyclo[2.2.1]hept-endo-2-yl trans-cinnamate and endo-5-[4'(5')-imidazolyl]bicyclo[2.2.2]oct-endo-2-yl trans-cinnamate in which the imidazolyl and trans-cinnamoyl groups are bound in close proximity to each other by rigid bicyclic rings. The rate constants for the intramolecular general base-catalyzed hydrolyses at 60 degrees are 6.4 X 10(-7) sec-1 for the former and 1.8 X 10(-7) sec-1 for the latter and the deuterium oxide solvent isotope effects are 3.0 for both. On the other hand, no intramolecular catalytic participation of the imidazolyl group was observed in the hydrolyses of the endo-exo isomers, exo- 5-[4'(5')-imidazolyl]bicyclo[2.2.1]hept-endo-2-yl trans-cinnamate and endo-5[4'(5')-imidazolyl]bicyclo[2.2.2]oct-exo-2-yl trans-cinnamate, in which the imidazolyl groups are located far from the trans-cinnamoyl groups. Intramolecular general base-catalyzed hydrolyses by the imidazolyl groups in endo-5[4'(5')-imidazolyl]bicyclo[2.2.1]hept-endo-2-yl trans-cinnamate and endo-5-[4'(5')-imidazolyl]bicyclo[2.2.2]oct-endo-2-yl trans-cinnamate can serve as models of serine esterase-catalyzed hydrolyses.

Catalysis↗

PubMed1976

Modified 5'-nucleotides resistant to 5'-nucleotidase: isolation of 3-(3-amino-3-carboxypropyl) uridine 5'-phosphate and N2, N2-dimethylguanosine 5'-phosphate from snake venom hydrolysates of transfer RNA.

A procedure for the quantitative measurement of the O2'-methylnucleoside constitutents of RNA has recently been developed in this laboratory (Gray, M.W. Can. J. Biochem. 53, 735-746 (1975)). This assay method is based on the resistance of O2'-methylnucleoside 5'-phosphates (pNm) (generated by phosphodiesterase hydrolysis of RNA) to subsequent dephosphorylation by venom 5'-nucleotidase (EC 3.1.3.5). In the present investigation, two base-modified 5'-nucleotides, each displaying an unusual resistance to 5'-nucleotidase, have been identified. These compounds have been characterized by a variety of techniques as N2, N2-dimethylguanosine 5'-phosphate (pm2/2G) and 3-(3-amino-3-carboxypropyl)uridine 5'-phosphate (p4abu3U). Because of their resistance to 5'-nucleotidase, pm2/2G and p4abu3U are isolated along with the pNm in the mononucleotide fraction of venom hydrolysates of transfer RNA. Under hydrolysis conditions, the stability of p4abu3U is comparable to that of a pNm, allowing quantitative assay of the nucleotide. The proportion (mean +/- SD) of p4abu3U in venom hydrolysates of wheat embryo and Escherichia coli tRNA has been determined to be 0.35 +/- 0.03 (n=5) and 0.14 +/- 0.02 (n=4) mol%, respectively. The absence of p4abu3U in venom hydrolysates of yeast tRNA implies the absence of the corresponding nucleoside in yeast tRNA, in agreement with existing data. The variable recovery of pm2/2G from venom hydrolysates of wheat embryo and yeast tRNA indicates that under hydrolysis conditions, this base-modified nucleotide is only partially resistent to 5'-nucleotidase. The complete absence of pm2/2G in venom hydrolysates of E. coli tRNA is consistent with the known absence of N2, N2-dimethylguanosine in this RNA. These observations demonstrate that resistance to 5'-nucleotidase is a necessary but not sufficient criterion for concluding that a 5'-nucleotide is O2'-methylated. When applied to wheat embryo ribosomal RNA, the analytical methods described in this report failed to reveal any compound having the distinctive charge properties of p4abu3U. It therefore appears that 1-methyl-3-(3-amino-3-carboxypropyl)pseudouridine, recently characterized as a constituent of the 18 S rRNA of Chinese hamster cells (Saponara, A.G. & Enger, M.D. Biochim. Biophys. Acta 349, 61-77 (1974)), may not be present in wheat embryo ribosomal RNA.

Guanine Nucleotides↗

PubMed2026

Olive leaf protein hydrolysates yield gastro-resistant peptides with antioxidant and anti-inflammatory potential: peptidomics, in vitro validation and molecular docking analyses.

Olive (Olea europaea L.) leaves are an abundant olive-oil by-product and a promising feedstock for sustainable valorisation. An olive leaf protein isolate (OLPI) from olive-leaf powder (OLP) was enzymatically hydrolysed to yield seven hydrolysates (OLPHs). All showed notable antioxidant activity as whole hydrolysate matrices (EC₅₀ = 0.11-0.28 mg mL-1); likely reflecting the combined contribution of released peptides and co-extracted phenolic compounds; the 15-min Alcalase product (OLPH15A) showed high activity with the shortest processing time. Its INFOGEST digest (dOLPH15A) attenuated LPS-induced inflammation in Caco-2 cells, down-regulating pro-inflammatory and up-regulating anti-inflammatory genes. Peptidomics identified 7037 peptides in OLPH15A and 534 in dOLPH15A, from which twenty gastro-resistant sequences were prioritised for in silico analysis. Multi-tool prediction and docking highlighted four peptides, GAAGGIGQPL, QSAYPGTGPL, GGGAGGGDGGIL and LDAQFPGVN, with favourable predicted affinity for the TLR4/MD2 complex, suggesting that they may contribute to the observed immunomodulatory response. These findings position olive leaves as a viable source of protein hydrolysate-based ingredients with antioxidant and anti-inflammatory potential, advancing the valorisation of olive-oil by-products.

Olea↗

PubMed1977

Chemical and immunological properties of a protein hydrolysate formula.

Clinical observation suggested that a protein hydrolysate formula designed to serve as an oral elemental diet was capable of producing untoward reactions in some children with malabsorption syndromes caused by cow milk protein allergy. An immunological study of the antigenicity of this hydrolysate was undertaken. Although it is claimed that the hydrolysate is produced from casein, it was shown that it produced, after injection into animals, precipitating antibodies against at least three of the whey proteins. Analysis of the molecular weight of this hydrolysate showed it to contain a polypeptide fraction with molecular weight above 3,850.

Animals↗

PubMedDate not supplied

[Nitrogen-containing fractions of Soviet hydrolysates for parenteral feeding].

The content of free amino acids, non-precipitable and precipitable trichloro-acetic acid peptides in Soviet-made hydrolysates for parenteral alimentation was determined. As shown, it is aminopeptide and aminosol that contain the greatest amounts of amino acids, fibrinosol and caseine hydrolysate carrying their least quantities, with aminocrovine and hydrolysine occupying an intermediate place in this respect. The quality of hydrolysates was assessed according to their biological value and to do so chemical numbers of essential amino acids were calculated and limiting factors determined. Fibrinosol and aminosol and to a somewhat lesser degree--casein hydrolysate were found to be best balanced as concerns their amino acids composition. Aminopeptide, hydrolysine and especially aminocrovine were manifestly inadequate by their biological value, since they contain limiting amino acids (isoleucine, cystine and methionine).

Amino Acids↗

PubMed1977

A trial of lactose hydrolysed milk in Australian Aboriginal children.

Weight gains in 50 young Australian Aboriginal children were studied in a blind controlled hospital trial of reconstituted, lactose hydrolysed milk powder (test) and full-cream milk powder (control). The mean weight gains (+/- SEM) were 4.80 +/- 0.80 g kg-1 day-1 for children receiving the lactose hydrolysed milk, and 2.20 +/- 0.75 g kg-1 day-1 for those receiving the normal milk P less than 0.0125). Weight gain of infants (that is, those under one year of age) in the control group was less than 10% of that in the test group (P less than 0.0025). Weight gain was higher in children fed hydrolysed milk irrespective of percentage of Standard Weight for Age or the presence or absence of recognizable symptoms of lactose intolerance. Lactose malabsorption appears to be a major factor in the growth retardation of Aboriginal children. It is recommended that lactose hydrolysed milk replace normal milk in the supplementary feeding of Aboriginal infants and children.

Animals↗

PubMed1979

Isolation from lactalbumin hydrolysate of a high molecular weight mitogenic factor.

A new mitogenic factor has been isolated from tissue culture grade lactalbumin hydrolysate. Incubation of postconfluent Swiss 3T3 cells in serum-free medium containing lactalbumin hydrolysate resulted in enhanced synthesis and release of plasminogen activator. Sephadex G-100 gel filtration of concentrated, dialyzed lactalbumin hydrolysate revealed two fractions, LH-FI and LH-FII. LH-FI elutes at the void volume, indicative of high molecular weight, and contains all plasminogen activator stimulatory activity of the original lactalbumin hydrolysate, whereas LH-FII has no activity. In addition, LH-FI also induces DNA synthesis in Swiss 3T3 cells in a dose-dependent fashion, 1 to 2 microgram/ml being equivalent to 10% fetal calf serum. Again, LH-FII is without effect. Induction of DNA synthesis in LH-FI or serum-stimulated quiescent sparse cells followed essentially identical kinetics at least through the first 20 h. Furthermore, LH-FI also enhances 3T3 cell growth. Preliminary results of Sepharose 4B filtration of LH-FI reveal the presence of five subfractions each with plasminogen activator stimulatory as well as mitogenic activity.

Animals↗

PubMed1977

[Treatment of corneal ulcers by hydrophilic lenses pre-soaked in proteolytic hydrolysates of the corneal stroma (author's transl)].

The faculty of confering to hydrophilic contact lenses the properties of corneal bandage made unable to swell has been investigated by saturating them with calf's corneal hydrolysate. The absorption and storage of the proteolytic hydrolysate (properties and collagenasic hydrolysate's technic of obtention is mentioned) by hydrophilic contact lenses are studied. The treatment of some corneal ulcers is related for 27 eyes from 20 patients. The results appear more suitable for torpic ulcers than for mechanical ulcers.

Contact Lenses, Hydrophilic↗

PubMed1976

Complete amino acid analysis of proteins from a single hydrolysate.

An analytical procedure which affords the precise amino acid composition of a protein or a peptide from a single hydrolysate is described. This method utilizes 4 N methanesulfonic acid containing 0.2% 3-(2-aminoethyl)indole, rather then 6N HCl as a catalyst for hydrolysis. The hydrolysis is carried out in vacuo (20 mu) at 115 degrees for 22 to 72 hours. Half-cystine is determined as S-sulfocysteine by treating the hydrolysate with dithiothreitol followed by an excess of tetrathionate. The values of all amino acids, including tryptophan and half-cystine, were close to the expected theoretical values for the proteins examined. The method has the advantage that the neutralized hydrolysate can be applied directly to an ion exchange column. Further, the method is capable of distinguishing between free sulfhydryl groups as S-carbosymethylcysteine and disulfides as S-sulfocysteine. A limitation of the procedure is that tryptophan remains sensitive to the presence of carbohydrate in the sample.

Amino Acids↗

PubMed1977

[Serum lipids in experimental atherosclerosis in guinea pigs treated with protein hydrolysate].

The authors carried out studies on 223 male guinea pigs, weighting from 350 to 500 gm, fed with a diet containing 0,3% of cholesterol, disolved in cow butter. A part of the animals were injected with protein hydrolysate every other day for a period of 140 days. The level of serum lipids-total cholesterol, beta-lipoproteins, phospholipids and total lipids was examined. They found significantly higher values in the animals, receiving cholesterol in comparison with the control animals-292.4:84.9; 139.4:59.3; 457.1:241.2; 105.5:62.0 respectively for, beta-lipoproteins, total cholesterol, total lipids and phospholipids. The administration of protein hydrolysate in a dose of 0,5 ml/100 gm of body weight affected favourably fat metabolism. The increase of serum fat-lipid components was less manifested in comparison with the nontreated atherosclerotic animals. The greatest difference was found in beta-lipoproteins (292.4:143.8) and total, lipids (457.1:300.8). Statistically significant difference was established in total cholesterol as well. (139.4:81.9). There was an impression that this effect was due to the protective action of aminoacids of the protein hydrolysate on the normal functions of liver and the favourable effect on the tunover of the administered cholesterol.

Animals↗

PubMedDate not supplied

[Morphological changes in the liver due to the parenteral administration of casein hydrolysate and aminopeptide].

In experiments set up on 30 mongrel rats kept for 10 days on a protein-free diet the influence of an intraperitoneal introduction of caseine hydrolysate or aminopeptide on the morphological structure of the liver was studied. It was found that introduction to rats of aminopeptide or caseine hydrolysate caused stabilization of morphological changes in the liver produced by protein fasting. However, with aminopeptide introduced after protein fasting positive morphological changes proved greater than with an analogous utilization of caseine hydrolysate.

Animals↗

PubMed1979

[Changes in the perfusion of the internal organs of rabbits with experimental atherosclerosis treated with a protein hydrolysate].

The authors examined the vascularization of the internal organs of rabbits with experimental atherosclerosis, induced by the method of Sapirstein with 86-Rubidium. The experiments were carried out on male rabbits of the strain Cincilla, fed with cholesterol in a dose of 0.2 gm/kg of body weight daily for a period of 90 days. Part of the animals were treated with protein hydrolysate in a dose of 5 ml/kg of body weight subcutaneously, but the remaining part of the animals-with saline. There was a reduced vascularization in heart, kidney, intestine, liver, adrenals, pancreas, and other internal organs in rabbits fed with cholesterol and treated with saline. Administration of protein hydrolysate had protective effect on the vascularization of the organs accumulation of 86-Rubidium in a large part of the animals presented values higher than rhose of the control group. The authors suggested that under the influence of amino-acids from the protein hydrolysate the state of the endothelial cells was stabilized and the local, feactions of vascularization were stimulated as well.

Animals↗

PubMed1979

[Irrigation of the internal organs and the effect of the protein hydrolysate, Hydroport, in deep burns in rats].

The authors caused buring of III to IV degree, 10--15% in rats of the Wistar strain. The animals were divided into 4 groups: 1) healthy; 2) burned-nontreated; 3) burned-treated with saline; and 4) burned-treated with hydrolysate. Saline and hydrolysate were administered immediately after thermic trauma, and vascularization was examined by means of radioisotopic methods (86Rb) six hours after burning. Increased blood flow in the internal organs was found 6 hours after inducing the thermic trauma, excluding the pancreas. Saline revealed a certain tendency to normalization of the circulation, but this effect was insignificant and could not be referred to all organs. The protein hydrolysate most sensitively and significantly corrected deviations as in almost all organs they reached practically the norm.

Animals↗