Maturation of urinary proteoglycan excretion

Urinary proteoglycan excretion was studied using two newly established methods in subjects aged between 1 and 22 years. Analysis of glycan moieties showed an age-dependent decrease from 9.1±5.5 (SD) g/mol creatinine (n=5) at the age 1–6 years to 1.9±1.3 (n=5,P<0.01) in those aged 16–22 years. Marked qualitative changes in the proteoglycan electrophoretic pattern occurred during the first and second years of life. Two major proteoglycan bands with a molecular weight of 50 kDa decreased in intensity so that the pattern resembled the adult configuration after 6 years of age. The latter consisted of a major band with a molecular weight of 80–100 kDa, the bands corresponding to a molecular weight of 50 kDa and lighter bands of molecular weight around 32 kDa. These changes may be related to functional maturation of the kidney as a whole and to an increase in the number of mature nephrons.     

Modified arabinogalactans from callus culture <Emphasis Type="Italic">Silene vulgaris</Emphasis> (M.) G.

The cultivation of Silene vulgaris (M.) G. callus culture on the nutrient mediums contained carbohydrates, phytohormones, nitrogen, and phosphate has led to the modification of the arabinogalactan structure from the cell walls. It was noticed that a sucrose concentration increase in the cultivation medium led to an increase of the arabinogalactan fragment yield with a molecular weight more than 300 kDa and a decrease of the yield of fragments with molecular weight less than 300 kDa. The sucrose concentration increase in the nutrient medium entailed the increase of arabinose and galactose content in the fragment with the molecular weight more than 300 kDa and a decrease in the fragment with a molecular weight of 100–300 kDa. On the nutrient medium containing a mix of sucrose and arabinose, the yield of the fraction with a molecular weight more than 300 kDa and the amount of arabinose residues increased, and the yield of minor fragments and the content of arabinose and galactose residues, included in these, decreased. On the medium containing an increased concentration of 2,4-dichlorphenoxyacetic acid, the yield of high-molecular fragment and the content of arabinose residues are two times increased. The decreasing of the amount of arabinose and galactose residues in the fragment with a molecular weight more than 300 kDa was observed at a lack of nitrogen or phosphate in the nutrient medium.     

Purification and Comparison of β-1,3-Glucan Binding Protein From White Shrimp (Penaeus vannamei)

A β-glucan binding protein (BGBP) was identified in both white (Penaeus vannamei) and blue shrimp (P. stylirostris) plasma. White shrimp BGBP was purified by affinity chromatography using immobilized laminarin, and its molecular and biological properties were described. White shrimp BGBP is a monomeric protein with a molecular mass of 100 kDa, similar to those described for other crustacean BGBPs. White and blue shrimp BGBPs can be detected with antisera against crayfish BGBP and brown shrimp BGBP. Both amino acid composition and N-terminal sequence are markedly similar to brown shrimp (P. californiensis) and crayfish (Pacifastacus leniusculus) BGBP, indicating that this recognition protein is present in freshwater and marine crustaceans.     

Fractionation and characterization of chitosan by analytical SEC and H NMR after semi-preparative SEC

Heterogeneity in molecular weight and degree of deacetylation (DDA) of chitosans from different sources and preparation methods were studied by fractionating chitosans, using semi-preparative SEC, and then determining molecular weight profiles of fractions by analytical SEC with multi-angle laser light scattering (SEC–MALLS), and degree of deacetylation (DDA) by ¹H NMR. Fractionation of two high molecular weight chitosans from different manufacturers, produced fractions that spanned a wide range of molecular weight (number-average M_n), from 65 to 400 kDa in one case, that was not evident when unfractionated material was directly analyzed by SEC providing M_n = 188 kDa and PDI = M_w/M_n = 1.73. In a second case, fractions ranged from 20 to 600 kDa with unfractionated M_n = 145 kDa and PDI = 1.83. Fractionation of low molecular weight chitosans also showed a broad range of molecular weight in the original material, however, the fractions obtained with the TSKgel G4000W column in the M_n range of 5–100 kDa were essentially monodisperse with PDIs between 1.0 and 1.4. The DDA of one low molecular weight chitosan (10 kDa) produced by nitrous acid degradation was dependent on the M_n of the fraction. This semi-preparative fractionation procedure revealed important compositional heterogeneities of chitosans not evident in unfractionated material, and permitted the production of monodisperse low molecular weight chitosans with homogeneous properties.     

Effect of molecular weight on the antioxidant property of low molecular weight alginate from Laminaria japonica

In this study, three alginate fractions with different molecular weights and ratios of mannuronic acid (M) to guluronic acid (G) were prepared by enzymatic hydrolysis and ultrafiltration to assess the antioxidant property of alginates from Laminaria japonica with molecular weight below 10 kDa. The antioxidant properties of different molecular weight alginates were evaluated by determining the scavenging abilities on superoxide, hydroxyl, and hypochlorous acid and inhibitory effect on Fe²⁺-induced lipid peroxidation in yolk homogenate. The results showed that low molecular weight alginates exhibited high scavenging capacities on superoxide, hydroxyl, and hypochlorous acid radicals and good inhibition of Fe²⁺-induced lipid peroxidation in yolk. By comparison, alginate A1 with molecular weight below 1 kDa and M/G of 1.84 had better scavenging activity on superoxide, hydroxyl, and hypochlorous acid radicals in vitro than A2 (1–6 kDa), A3 (6–10 kDa), ascorbic acid, and carnosine. With similar M/G ratio, A2 exhibited better antioxidant activity on superoxide and hypochlorous acid radicals than A3. However, fraction A3 with molecular weight of 6–10 kDa exhibited higher inhibitory ability on lipid peroxidation in yolk in vitro than A1 and A2. The results indicated that molecular weight played a more important role than M/G ratio on alginate to determine the antioxidant ability. By comparison, low molecular weight alginates composed of guluronic acid and mannuronic acid exhibited better antioxidant ability on oxygen free radicals than sulfated polysaccharides from L. japonica in our previous study and represent a good source of marine polysaccharide with potential application as natural antioxidant.     

A solid phase assay for galactosyl transferases. Evidence for an active site of less than 14 kDa

Galactosyltransferase (GalTase) prepared from human milk was found to exist as a complex with e-lactalbumin as demonstrated by crossed immunoelectrophoresis against specific antibodies raised against the complex. GalTase activity was stable to proteolysis and, when subjected to gel filtration on Ultrogel AcA54, the enzyme activity eluted as a single peak. A second peak of activity was found to be adsorbed to the column matrix and was eluted with buffer containing 1 M NaC1. The hydrophobic fraction represented 5% of the total GalTase activity in human milk. After polyacrylamide gel electrophoresis the main enzyme activity peak was represented by polypeptides of 67kDa molecular weight and of 14kDa molecular weight. Electroblotting of these peptides onto a nitrocellulose membrane followed by determination of GalTase activity showed activity for 45–55 kDa and for 14 kDa peptides. The hydrophobic fraction from the AcA54 column was resolved into polypeptides of 110 kDa-45 kDa molecular weight, all of which contained GalTase activity after blotting. It is supposed that the GalTase from non-proteolyzed milk is composed of a 14 kDa polypeptide containing the active site together with another part of the polypeptide backbone which is involved in the regulation of GalTase activity by -lactalbumin, a third part of the polypeptide is responsible for the membrane insertion.Abbreviations UDP-Gal uridine diphosphatidyl galactose - GlcNAc N-acetylglucosamine - Glc glucose - PAGE polyacrylamide gel electrophoresis - GalTase galactosyl transferase (EC 2.4.1.22) - -ovo pronosac digest fraction of hen ovomucoid To whom correspondence should be addressed.     

Protein and Peptide Factors from Bacillus sp. 739 Inhibit the Growth of Phytopathogenic Fungi

Thermolabile peptides inhibiting the growth of Helminthosporium sativum, a facultative phytopathogen, have been isolated from the low-molecular-weight fraction of extracellular metabolites of the strain Bacillus sp. 739. Paper chromatography of the fraction, followed by bioautography, revealed the presence of three components exhibiting antifungal activity. These components were separated by gel chromatography on Toyopearl HW-40. SDS-Na-PAGE (the Laemmli procedure) demonstrated that only one component was a protein (MW, 14 kDa). The other two substances were polypeptides with molecular weights less than 6 kDa each. The protein factor inhibited the growth of H. sativum with a minimum effective concentration of 0.1 to 0.2 mg/ml.     

Accumulated forms of thallium and cadmium in Lemna minor. II. Relationship between duration of exposure and metal-protein binding

Abstract

Gel filtration chromatography (with Sephadex G25, G50 and G100) was used to separate the different forms of thallium (Tl) and cadmium (Cd) in the cytosol fraction of Lemna minor and to examine the influence of the duration of metal exposure on the speciation of the two elements. A major proportion of Cd in the soluble phase was found to be bound to three groups of proteinaceous and polypeptide fractions; two of these, the high molecular weight protein fraction (Mr > 150,000) and the low polypeptide sized moieties of about M_r 1,500 or less were constitutive entities, whereas the intermediate sized fraction (Mr 7,000 - 8,000) could only be detected in plants previously exposed to Cd. After 12 days of exposure to Cd this fraction accounted for the greatest part of the bound Cd in Lemna tissues. Extending the period of exposure from 18 hours to 12 days resulted in a shift in the distribution of Cd between the low and intermediate fractions. Evidence for Tl-protein binding was limited and confined to the high molecular weight fraction, and most of the Tl in the soluble phase was present in a form closely allied to the free ion. The contrasting behaviour between the two elements has been interpreted in terms of the differences in their physicochemical properties.     

Subunit organization of PSI particles from brown algae and diatoms: polypeptide and pigment analysis

P700 enriched fractions were isolated from two brown algae and one diatom using sucrose density centrifugation after digitinin solubilization. They had a Chl a/P700 ratio of about 250 to 375 according to the species, they were enriched in long-wavelength absorbing Chl a and exhibited a fluorescence emission maximum at 77 K near 720 nm. They all presented a major polypeptide component at 66±2 kDa, but their polypeptide composition was rather complex and somewhat different from one species to another. Further solubilization with dodecylmaltoside of those native PSI particles allowed the separation of two or three fractions. The lightest, xanthophyll-rich, fraction was identified to be a light-harvesting complex. It contained no P700 and had a major polypeptide of molecular weight near 20 kDa (at the same molecular weight than the respective LH native fraction of each species) and exhibited a 77 K peak fluorescence emission at 685 nm. The other fractions were enriched in P700 and almost entirely depleted in xanthophylls. When two of them are present, they both exhibited a major polypeptide at 66±2 kDa and were totally devoid of the LH polypeptide, but the two fractions widely differed one from another in the abundance and molecular weight of the other polypeptide components. The most purified of these two fractions presented a composition similar to PSI core complex from green plants.Abbreviations LH light-harvesting - LHCII light-harvesting complex II of green plants - P700 reaction center chlorophyll of PSI     

Lipophorin and its Receptor in Lepidoptera

Lipophorin (Lp) has an approximate native molecular weight of 730 kDa for Bombyx mori and consists of ApoLp‐I and ApoLp‐II with molecular weights of 250 kDa and 90 kDa for B. mori and 230 kDa and 80 kDa for Hyphantria cunea and 230 kDa and 49 kDa for Lymantria dispar, respectively. Lipid in Lp was mostly composed of neutral lipid. Lp of B. mori maintains constant level during larval and pupal stages but greatly increases during adult stage in both male and female. Lp of H. cunea appeared in great amounts in protein yolk bodies of ovary when vitellogenesis is actively taking place and was present in testicular fluid but not in the peritoneal sheath and cysts of testis. ApoLp‐III of B. mori has a molecular weight of 17 kDa and similar amino acid composition as those of other species Lp. H. cunea apoLp‐III has a molecular weight of 18 kDa and was present in all stages and in the protein body of ovary and in the cyst of testis. ApoLp‐III is synthesized in larval and adult fat body. cDNA sequence of Spodoptera litura apoLp‐III encodes a 188 amino acid polypeptide including a 22 amino acid leader peptide. Galleria mellonella Lp receptor has an approximate molecular weight of 97 kDa and 110 kDa under non‐reducing and reducing conditions, respectively and bound HDLp specifically. Lp receptor cDNA of G. mellonella showed th pattern of the VLDL receptor belonging to the LDL receptor family. The variant Lp receptors were expressed in the fat body of G. mellonella; one is a Lp receptor which lacks 84 bp of O linked sugar domain and the other is a full length form of the Lp receptor. The Lp receptor from the fat body of G. mellonella was differently expressed depending on the tissue and the developmental stages with specific abundance in prepupal stage.     

Low-molecular weight peptides isolated from seahorse (Hippocampus abdominalis) improve vasodilation via inhibition of angiotensin-converting enzyme in vivo and in vitro

According to relevant literature, the consumption of seahorses has been used to increase male functions by improving blood flow and decreasing blood pressure. Thus, it was theorized that seahorses may also be effective against hypertension. Herein, vasodilation caused via the inhibitory effect of angiotensin-converting enzymes (ACEs) in peptides was elucidated by studying the seahorses (Hippocampus abdominalis) farmed at Jeju in South Korea. Hydrolysate was prepared using the Protamex (SHP) enzyme. The ultrafiltration system was adopted to separate certain fractions from SHP according to different molecular weights (SHP-I, MW > 10 kDa; SHP-II, MW = 5−10 kDa; SHP-III, MW < 5 kDa). The fraction with the lowest molecular weight (SHP-III) and with a low IC₅₀ value (0.044 ± 0.005) for the ACE inhibitory effect was further separated by Sephadex G-10. Three ACE inhibitory peptides from SHP-III were isolated and identified using the Q-TOF mass spectrometer (Ala-Pro-Thr-Leu, Cys-Asn-Val-Pro-Leu-Ser-Pro, and Pro-Trp-Thr-Pro-Leu). Furthermore, SHP-III-induced systolic blood pressure varied with the concentrations, as observed in the spontaneously hypertensive rat (SHR). SHP and the isolated peptides were observed to show vasodilation via ACE inhibitions and resulted in lowering the blood pressure of the SHR. These results imply that peptides from seahorses can augment male functions.     

Analysis of the Molecular Organization of Photosystem I During Light-Dependent Chloroplast Differentiation in Mutant C-6D of Scenedesmus obliquus*

Cells of pigment mutant C-6D of the green alga Scenedesmus obliquus synthesize only Chl a and precursors of carotenoids during heterotrophic growth in the dark. These cells exhibit high PSI-activity per Chl and a low Chl/P700-ratio. After transfer to light, Chl a, Chl b and carotenoids are formed with different kinetics. Analysis of chlorophyll fluorescence emission and excitation spectra revealed a sevenfold increase in the amount of the long wavelength antenna of PSI (720 nm) resulting in an increase in the absorption cross section of PSI during illumination. The underlying changes in molecular organization of PSI were investigated by sucrose density centrifugation of solubilized thylakoids after digitonin treatment and subsequent identification of the components by gel electrophoresis, HPLC and fluorescence. In dark grown cells one blue-green band (0-II) could be resolved. This band contained only Chl a and the reaction center complex of PSI, CPI. After 24 hours of illumination three pigmented zones and a small amount of free pigment were observed. One of the zones (24-I) was identified as a light-harvesting fraction containing the pigment-protein complexes LHCP₁ and LHCP₃. In the second fraction (24-II) the reaction center complexes of PSI and PSII were found. The highest molecular weight fraction (24-III) was enriched in PSI-complexes of higher molecular weight and contained a high amount of long wavelength fluorescence antenna (720 nm) attributed to PSI. In contrast to band 24-II which contained a high percentage of β-carotene and a high Chl a/b-ratio, the Chl a/b-ratio of fraction 24-III was lower and the xanthophyll content increased. Our data demonstrate an increase in the PSI-unit size during chloroplast development in mutant C-6D of Scenedesmus obliquus. Dark-grown cultures have small functional PSI-units composed of the chlorophylls involved in charge separation and the core antenna. This unit contains only Chl a and no carotenoids. After transfer to light Chl b and carotenoids are formed. Simultaneously with the appearance of carotenoids and Chl b, PSI-complexes of higher molecular weight are synthesized indicating the addition of a LHC to the reaction center complex of PSI.     

β-Endorphin and ACTH related peptides in primary cultures of rat anterior pituitary cells: evidence for different intracellular pools

Acid extracts of rat anterior pituitary cells and cell-derived culture media were shown to contain three forms of β-endorphin immunoreactive peptides, corresponding in molecular size to the prohormone pro-opiomelanocortin (POMC), β-lipotropin and 3.5 kDa β-endorphin, and essentially two forms of adrenocorticotropin (ACTH) immunoreactivity, representing a 20 kDa intermediate fragment and 4.5 kDa ACTH. Under basal conditions the intracellular peptides contained a high proportion of the bioactive forms of β-endorphin and ACTH whereas the extracellular peptides contained a higher proportion of the inactive precursors. When the cells were incubated for 3 h in the presence of 10⁻⁸ M CRF, the levels of intracellular β-endorphin and ACTH immunoreactivity were reduced by 15–30% and there was a 4–5-fold increase in the level of the secreted peptides; furthermore, unlike the peptides released under basal conditions, the peptides secreted under the influence of CRF contained much higher proportions of 4.5 kDa ACTH and 3.5 kDa β-endorphin, reflecting the intracellular patterns of these peptides. Similar results were obtained when secretion was stimulated by 10⁻⁷ M epinephrine, which produced a 2-fold increase in peptide release. In the presence of 10⁻⁶ M dexamethasone the basal secretion of ACTH and β-endorphin related peptides, and the intracellular levels of these peptides, remained unaltered. The results point to the existence of different intracellular compartments from which peptides at different states of maturation can be released selectively.β-EndorphinACTHPituitary cell cultureProcessingCRFEpinephrine     

Improved methods to detect GTP-binding proteins from plants

Improved methods are described for the detection of G1P-binding proteins (G-proteins) in the protonema of mossFunaria hygrometrica and coleoptiles of corn(Zea mays) and sorghum(Sorghum vulgare). We optimized conditions for the transfer of proteins to nitrocellulose, production of high titer polyclonal anti-Gα (common) antibodies and finally the detection of G-proteins by amplification. In addition to the α-subunit of heterotrimeric G-proteins (M _r 41–43 kDa), a small molecular weight class (< 30 kDa) was also detected by anti-Gα (common) antibodies. An easy, reliable and efficient filter assay is also described to quantify the toxin catalyzed ADP-ribosylation. The apparentK _m of the NAD has been determined to be approximately 1.5μM for the microsomal fraction of moss. Inclusion of G1P stimulated ADP-ribosylation by 2–27-fold. One to three polypeptides representing the α-subunit of heterotrimeric G-proteins of (M_r 37–43 kDa) were ADP-ribosylated in all three plants. The anti-Gβ (C-terminus) antibody cross-reacted strongly with 39 and 34 kDa polypeptide in moss and corn respectively. By employing improved methods two classes of G-proteins have been shown to be present in three plant species.     

Physico-chemical properties of R140G and K141Q mutants of human small heat shock protein HspB1 associated with hereditary peripheral neuropathies

Some physico-chemical properties of R140G and K141Q mutants of human small heat shock protein HspB1 associated with hereditary peripheral neuropathy were analyzed. Mutation K141Q did not affect intrinsic Trp fluorescence and interaction with hydrophobic probe bis-ANS, whereas mutation R140G decreased both intrinsic fluorescence and fluorescence of bis-ANS bound to HspB1. Both mutations decreased thermal stability of HspB1. Mutation R140G increased, whereas mutation K141Q decreased the rate of trypsinolysis of the central part (residues 5–188) of HspB1. Both the wild type HspB1 and its K141Q mutant formed large oligomers with apparent molecular weight ∼560 kDa. The R140G mutant formed two types of oligomers, i.e. large oligomers tending to aggregate and small oligomers with apparent molecular weight ∼70 kDa. The wild type HspB1 formed mixed homooligomers with R140G mutant with apparent molecular weight ∼610 kDa. The R140G mutant was unable to form high molecular weight heterooligomers with HspB6, whereas the K141Q mutant formed two types of heterooligomers with HspB6. In vitro measured chaperone-like activity of the wild type HspB1 was comparable with that of K141Q mutant and was much higher than that of R140G mutant. Mutations of homologous hot-spot Arg (R140G of HspB1 and R120G of αB-crystallin) induced similar changes in the properties of two small heat shock proteins, whereas mutations of two neighboring residues (R140 and K141) induced different changes in the properties of HspB1.     

Purification and properties of the raw-starch-digesting glucoamylases from Corticium rolfsii

Corticium rolfsii AHU 9627, isolated from a tomato stem, is one of the strongest producers of a raw-starch-digesting amylase. The amylase system secreted by C. rolfsii AHU 9627 consisted of five forms of glucoamylase (G1–G5) and a small amount of α-amylase. Among these amylases, G1, G2 and G3 were able to hydrolyze raw starch. Five forms of glucoamylase were separated from each other and purified to an electrophoretically homogeneous state. The molecular masses were: G1 78 kDa, G2 78 kDa, G3 79 kDa, G4 70 kDa, and G5 69 kDa. The isoelectric points were: G1 3.85, G2 3.90, G3 3.85, G4 4.0, and G5 4.1. These glucoamylases showed nearly identical characteristics except that G4 and G5 were unable to hydrolyze raw starch. Received: 16 December 1997 / Received last revision: 6 May 1998 / Accepted: 1 June 1998     

Antioxidant activity of the simulated gastro-intestinal digestion hydrolysate of two edible Nigerian marine molluscs: Tympanatonus fuscatus var radula (L.) and Pachymelania aurita (M.)

The multifunctional nature of antioxidant peptides makes them more attractive candidates as dietary ingredients in health maintenance. Therefore, food protein-derived antioxidant peptides are continuously investigated. This study investigated the in vitro antioxidant properties of hydrolysate and ultrafiltered peptide fractions of Pachymelania aurita and Tympanatonus fuscatus var radula-two commonly consumed marine molluscs known as periwinkles in southern Nigeria. Simulated gastrointestinal digestion (SGID) of soluble proteins of T. fuscatus and P. aurita was carried out using pepsin, trypsin and chymotrypsin, and the SGID hydrolysates were fractionated using a 3 kDa membrane filter. The hydrolysates and their fractions were investigated for anti-lipid peroxidation, hydroxyl radical scavenging activity (HRSA), ferric reducing antioxidant property (FRAP) and metal chelation activity, and they demonstrated clear antioxidant properties in all the assay models used. Low molecular weight fractions of the hydrolysates demonstrated more potent antioxidant activity than higher molecular weight fractions. This is profound in the metal chelation assay, where low molecular weight peptide fractions, T ≤ 3 kDa and P ≤ 3 kDa (IC₅₀ values of 8.10 ± 0.011 and 5.56 ± 0.50 µg/ml respectively) had activity that is similar to that of EDTA (11.84 ± 0.89 µg/ml). Similar activity effects were observed in other assays where there was about 3-fold higher activity in low molecular weight fractions. These results demonstrate the presence of antioxidant peptide(s) in the protein hydrolysates of the periwinkles.     

The influence of alkali and heat treatment on yeast protein

The soluble components in disintegrated cells of Saccharomyces cereivisiae have been characterized by means of extraction, centrifugation, dialysis, and gel filtration. The influence of alkali and heat treatment on the protein and RNA in the soluble fraction from disintegrated yeast cells and on functional properties of protein concentrates have been studied. After water extraction and centrifugation at 100000 g 42% of the nitrogen containing components of the disintegrated cells were recovered in the supernatant. By extraction at pH 11.5 an additional 31% of the nitrogen was solubilized. Half of the water-soluble nitrogen-containing components has a molecular weight lower than 5000. In the water- and alkali-soluble fractions about 80% of each amino acid was recovered The water-soluble protein was separated into 3 fractions by gel filtration on Sephadex G 200. The major portion of the protein had a molecular weight about 100,000. The amount of protein in this fraction was decreased after treatment at increasing pH and temperature. No degradation of protein to low molecular peptides occurred. The amount of RNA in the soluble fraction was only slightly influenced by alkali treatment and by heat treatment at pH 7.5 in the presence of 5% NaCl. RNA was not degraded to low molecular components of the treatments. The solubility of protein concentrates decreased after treatment at alkaline pH and after heat precipitation.     

New Insights into the Antimicrobial Properties of Hydrolysates and Peptide Fractions Derived from Chia Seed (Salvia hispanica L.)

Bioactive peptides derived from chia (Salvia hispanica) seed with antioxidant, antihypertensive, and anti-inflammatory activities have been well documented; however, few studies describe the antimicrobial properties of these peptides, which is of great interest not only in the prevention of food-borne diseases but also food spoilage. The aim of this study was to generate chia seed peptides using microwave-assisted hydrolysis with sequential (alcalase + flavourzyme) enzymes (AF-MW), fractionate them into 3–10 and < 3 kDa fractions, and evaluate their potential antimicrobial activity towards Escherichia coli, Salmonella enterica, and Listeria monocytogenes. Overall, the peptide fraction < 3 kDa showed higher antimicrobial activity than both chia seed hydrolysate and peptide fraction 3–10 kDa. Furthermore, the < 3 kDa fraction showed remarkable increase in membrane permeability of E. coli (71.49% crystal violet uptake) and L. monocytogenes (80.10% crystal violet uptake). These peptides caused a significant extension in the lag phase, decreases in the maximum growth, and growth rate in the bacteria and promoted multiple indentations (transmembrane tunnels), membrane wrinkling, and pronounced deformations in the integrity of the bacterial cell membranes. Finally, a select group of peptides in the AF-MW < 3 kDa fraction contained 16 sequences with cationic and hydrophobic character, with seven of them sharing the exact same sequence (GDVIAIR) and eight of them having the amino acid K as either N- or C-terminal or both. In conclusion, our results indicate that bioactive peptides obtained from chia seed proteins by microwave and enzymatic hydrolysis could be employed as antimicrobial agents in foods and therapeutic applications.