Proteolytic Changes Research Articles

Abstract A091: Ezrin functions as a metastasis-associated protein by regulating multiple steps involved in breast cancer cell dissemination

Abstract The membrane cytoskeleton cross-linker ezrin, is frequently up-regulated in many aggressive cancer types including breast, and is linked to metastatic progression. However, the underlying molecular mechanisms that delineate how ezrin may be involved in the cancer cell dissemination process remain unclear. In this study, we sought to determine the precise role of ezrin in several key components of the metastatic cascade, namely angiogenesis, cell migration, invasion, and lung seeding, in order to gain a comprehensive understanding of the function of ezrin as a metastasis-associated protein. By depleting ezrin expression in MDA-MB-231 invasive breast carcinoma cells, we demonstrate using ex vivo aortic ring and in vivo Matrigel plug assays that ezrin is required for promoting angiogenesis, thereby providing a critical escape route for tumor cells. We further show that the endogenous levels of vascular endothelial growth factor-A (VEGF-A), a potent angiogenic regulator, are significantly reduced in ezrin-depleted cells. Interestingly, secretion of interleukin-6 (IL-6), a known regulator of VEGF-A expression and myeloid cell recruitment, and activation of its downstream effector signal transducer and activator of transcription 3 (Stat3) were also markedly inhibited in these cells, thus suggesting a critical role for ezrin in mediating angiogenesis and potentially pre-metastatic niche priming. Using real-time microscopy, we found that ezrin-deficient cells displayed impaired focal adhesion and invadopodia dynamics, resulting in increased cell-ECM attachment, reduced migration and invasion, though no change in proteolysis was observed. Furthermore, ezrin-depleted cells exhibited significantly less directionality in their movement and were defective in their ability to migrate through an endothelial cell barrier by affecting tight junction permeability. These findings suggest that ezrin may be involved in facilitating intra/extravasation. One of the final stages of cancer cell dissemination is colonization at a distant organ site. Indeed, in vivo lung seeding experiments revealed that fewer ezrin-depleted cells remained in the lung 24 h post-injection, and ultimately led to a reduction in the number of tumor nodules. Collectively, our results unveil a novel coordinate role for ezrin in regulating metastatic progression, and provide important insight in evaluating ezrin as a potential prognostic/predictive marker for metastatic relapse in human breast cancers. (Supported by Canadian Institutes of Health Research, CIHR; Canadian Breast Cancer Foundation Doctoral Fellowship Program; and the Terry Fox Training Program in Transdisciplinary Cancer Research). Citation Format: Victoria Hoskin, Abdi Ghaffari, Alvin Szeto, Bruce E. Elliott. Ezrin functions as a metastasis-associated protein by regulating multiple steps involved in breast cancer cell dissemination. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A091.

Physico‐chemical, biochemical and microbiological changes of Kumpia wieprzowa during ripening

PurposeThe purpose of this paper is to estimate physico‐chemical, biochemical and microbiological changes during the three‐month ripening of the Polish traditional raw smoked fermented meat product Kumpia wieprzowa, produced from pork shoulder without fore‐shank.Design/methodology/approachAfter one, two and three months, the pH, aw, chemical composition, the content of nitrogen – total and soluble – as well as the profile of aromatic compounds and microflora, were evaluated.FindingsDuring ripening, the water content decreased from 62.7 percent to 47.5 percent, while the protein and fat amount increased from 20.8 percent to 25.0 percent and from 9.7 percent to 16.3 percent, respectively; the aw decreased from 0.95 to 0.88 and pH from 5.80 to 5.35. The proteolytic changes, measured by free amine groups and Nsoluble content, as well as the quantity of free fatty acids and percentage of most of the volatile compounds increased, particularly during the first two months of ripening. The total number of aerobic microorganisms, and Lactobacillaceae decreased during ripening from 7.9 to 6.2 and 5.6 to 4.7 log cfu/g, respectively. The count of coagulase‐negative cocci changed from 5.3 to 5.2 log cfu/g.Originality/valueKumpia wieprzowa is a unique pork product, entered on the List of Polish Traditional Products in 2005. Up to the present, the properties of Kumpia wieprzowa were not recognized and published in the scientific literature, in spite of its very interesting raw material (shoulder spontaneously fermented as a whole large primal cut).

Proteolytic pattern of myofibrillar protein and meat tenderness as affected by breed and aging time

The effects of breed and aging time (1, 7, 14, 21days) were evaluated on meat tenderness and on proteolysis in 24 young bulls from Romagnola×Podolian crossbreed, Podolian and Friesian breed. Shear force decreased with aging in all breeds and showed the highest values at 1 and 7days in Podolian meat. Myofibrillar fragmentation index significantly increased in Podolian meat throughout aging whereas in Friesian and in Crossbreed meat it increased only in the first week. Proteolysis was investigated by SDS-PAGE and 2-dimensional electrophoresis showing a different quantity and expression profile of myofibrillar proteins among breeds. In all breeds a decrease of troponin-T and an increase of troponin-T derived polypeptides during aging were observed. The highest decrease of troponin-T together with the presence of fragments of MHC in Podolian meat during aging was an outcome of a more extensive proteolysis in this breed. Data suggest that tenderness and proteolytic changes during aging are related to animal's breed.

Proteolytic Activity in Actomyosinfrom Mantle and Fin of Squid (Illexargentinus) Stored at 2-4°C. Influence on the Physicochemical and Functional Properties of the Protein

<p>Actomyosin (AM) of mantle and fin from squid was stored at 2-4°C and the possible presence of proteolytic activity was investigated. Similar SDS-PAGE 10% patterns were obtained with both AM at zero time of storage. In absence of protease inhibitors, a decrease in the intensity of the band of the myosin heavy chain (MHC) and an increase in those of 155 kDa and 55 kDa bands of stored AM was observed. In presence of either PMSF (phenylmethylsulfonyl fluoride) or EDTA (ethylenediaminetetraacetic acid) both AM showed a minor degradation of the MHC, being the EDTA more effective. Proteolytic changes were accompanied by a significant increase (p < 0.05) in the proteinsurface hydrophobicity, (So: 1-anilino-8-naphtalene sulfonic acid (ANS)), the emulsion activity index (EAI) and the emulsion stability (ES) at 24 h of storage. At the same time, the reduced viscosity (VER) decreased significantly (p < 0.05). No significative changes (p > 0.05) in VER, IAE and ES of both AM occur in presence of protease inhibitors.A proteolytic activity closely associate with actomyosin from squid mantle and fin, was detected. Both serine and metalloproteinase activities were responsible for the autolysis of stored actomyosin. The best emulsifiying properties were obtained with AM without inhibitors. Because of this fins proteins could be and inexpensive source of functional ingredients with potential application as emulsifier agents in food product.</p>

Stability of AMH measurement in blood and avoidance of proteolytic changes

The new Gen II assay for anti-Müllerian hormone (AMH) shows good stability and reliability in serum, but analyses of stability in whole blood are lacking. Testing the effects of storage of whole-blood samples at room temperature revealed significant increases in the measured value of AMH of 31% over 4days (P<0.001). The effect is temperature dependent, with storage at 4°C showing markedly reduced increments. Further, samples collected into serum tubes with gel separators and centrifuged within 5h (blood cells and serum physically separated within the collection tube) showed reliable stability over a period of more than 5days.

Effects of calpastain (CAST) polymorphisms on carcass and meat quality traits in Mongcai pigs

Calpastain (CAST) activity plays a major role in muscle growth and proteolytic changes post-mortem and the CAST gene has been considered as a candidate gene for carcass and pork quality characteristics. The aim of this study was to analyze the association of two polymorphisms namely CAST_HinfI (allele A and B) and CAST_MspI (allele C and D) with carcass and meat quality traits in Mongcai, a Vietnamese indigenous pig breed. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to genotype the animals at these loci. Results indicate that the CAST_HinfI single nucleotide polymorphism (SNP) had a low frequency of allele A as compared to allele B, while the C and D allele distribution was almost the same for the CAST_MspI SNP. In the association analysis, significant effects on dressing percentage of carcass were detected. The CAST_HinfI locus was associated with the pH24, while the CAST_MspI position was in association with pH45 min, drip loss48 and redness color. Additional analysis showed a variation in muscle fiber type composition with higher proportion of IIx fiber in pigs with AB genotype (P < 0.05). Three constructed haplotypes namely AB/CD, AB/DD and BB/CC also had significant effects on carcass, type IIa and IIb fiber percentages.

Proteolysis and biogenic amines formation during the ripening of Petrovská klobása, traditional dry-fermented sausage from Northern Serbia

Proteolytic changes and formation of biogenic amines in Serbian traditional dry-fermented sausage were determined during 120 days long ripening period. The sausage was made during winter (low ambient temperature) without the use of additives and microbial starters, resulting in slow decrease in water activity (aw) and pH. The aw gradually decreased from initial value of 0.95 to 0.86 (P < 0.05), while pH drop was slight (about 0.4 units) with the minimum (5.30) recorded after 60 days of ripening. The Lab-on-a-Chip (LoaC), electrophoresis based method, was used for qualitative assessment of the proteolytic changes in the sarcoplasmic and myofibrillar proteins. Obtained results showed that proteolysis was not intense, reflecting on slow degradation of sarcoplasmic proteins and myosin heavy chain, and complete absence of actin degradation. Total level of biogenic amines ranged from 113 to 332 mg/kg dm throughout ripening, while histamine, as the most important biogenic amine in terms of food safety, was not detected in any analyzed sample.

Proteolytic activity and vascular changes during revascularization of skin grafts

Proteolytic activity and vascular changes during revascularization of skin grafts

SUCUK (TURKISH-STYLE DRY-FERMENTED SAUSAGE) QUALITY AS AN INFLUENCE OF RECIPE FORMULATION AND INOCULATION OF STARTER CULTURES

ABSTRACT Six variants of beef, mutton and goat sucuk without (B, M, G) and with (Bs, Ms, Gs) starter cultures were examined. Chemical composition, proteolytic changes, color and sensory quality were observed. Starter variants had greater (P < 0.05) weight loss (1.12–3.04%) and lower moisture content at production end (1.05–1.31%). pH reached minimum 4.80–4.91 (day 14) in variants with starters, while variants without starters 5.10–5.13 (day 30). Earlier disappearance of bands 100, 37–46 and 10 kDa was observed in sarcoplasmic protein pattern of starter variants. Starter cultures had no major effect on myofibrillar proteins. Starter variants had greater L* values (47.07, 49.28, 50.45 as opposed to 42.81, 42.92, 45.87) and b* values (except B/Bs – 9.62, 11.53, 10.48 as opposed to 8.54, 9.87, 9.02). Assessors noticed greatest influence of starters on color, texture and taste. Application of starters had positive effects. Goat meat and mutton can be used with slight recipe modifications. PRACTICAL APPLICATIONS Sucuk, dry-fermented sausage, is very common in the Middle East, Middle Asia and Southeastern Europe, and is one of the three most widespread fermented sausages in Serbia. Manufacturing of sucuk varies regionally, but in general, sucuk recipes consist of beef and beef fat and/or sheep tail fat. Sheep and goat farming is traditional in some parts of Serbia, and during the past years it has been on the increase (in some other parts of the country as well) because of dairy products. It was deemed necessary to establish the possibility of use of other types of meat available in a certain area (not only in Serbia, but also worldwide). Furthermore, according to data in written sources, the use of starter cultures may contribute to safety and sensory quality of the product.

Identification of biomarkers of meat tenderisation and its use for early classification of Asturian beef into fast and late tenderising meat

The objective of this work was to study the post-mortem evolution of potential biomarkers (µ-calpain activity and proteolytic profile) of meat tenderisation in bovine longissimus dorsi (LD) muscle from several biotypes coming from two beef breeds ('Asturiana de los Valles' and 'Asturiana de la Montaña') and showing different levels of muscular hypertrophy (mh/mh, mh/+, + /+). LD samples were taken at 2, 12, 24 and 48 h and 3, 7, 14 and 21 days post-mortem. The presence of muscular hypertrophy produced a faster rate of pH decline, faster exhaustion of µ-calpain activity and earlier occurrence of proteolytic changes. Changes in the electrophoretic pattern of some peptides from sarcoplasmic (glyceraldehyde-3-phosphate dehydrogenase) and myofibrillar (troponin T and troponin I) muscle extracts within the first 24 h significantly correlated with meat toughness and allowed accurate discrimination of meat products into two groups: (1) fast tenderising meat, coming from mh-biotypes, and (2) late tenderising meat, from normal (+/+) biotypes. Early monitoring (within 24 h after slaughter) of selected biomarkers in LD muscle allowed accurate prediction of ultimate meat toughness and could be used in the meat industry as a tool for early classification of beef into fast and late tenderising meat.

Evaluation of proteolytic and physicochemical changes during storage of fresh Panela cheese from Queretaro, Mexico and its impact in texture

Mexican Panela cheeses manufactured with pasteurized cow's milk at a pilot plant scale were analyzed in order to determine the relationship between physicochemical and textural changes during 15-day storage. Changes in hardness, cohesiveness, springiness and chewiness were measured by texture profile analysis (TPA). Moisture, pH (superior and inferior rind and center) and total protein were evaluated with official methods. Proteolytic indexes (acid soluble nitrogen (ASN), non-protein nitrogen and 70% ethanol soluble nitrogen (EtOH-SN)) were obtained by selective precipitation and quantified by Kjeldahl method. Organic acids (lactic (LA), propionic (PA) and butyric acid (BA)) quantitation was done by high performance liquid chromatography. Analysis of variance (ANOVA) showed significant differences for all the physicochemical parameters evaluated, but only cohesiveness and springiness showed significant differences in texture parameters. By principal component analysis (PCA) two groups were separated, one from day 1 to 7 and one from day 9 to 15.

EFFECT OF SUGAR LEVEL ON PHYSICOCHEMICAL, BIOCHEMICAL CHARACTERISTICS AND PROTEOLYSIS PROPERTIES OF CANTONESE SAUSAGE DURING PROCESSING

ABSTRACTThe effects of sugar levels (3, 6, 9, 12%, w/w) on gross composition, the main physicochemical parameters, microbiology, protein composition and proteolytic change of water soluble protein (water soluble nitrogen [WSN]) of Cantonese sausage were evaluated. The sample with 12% sugar addition had low aw as well as pH values. During processing, sarcoplasmic and myofibrillar protein content decreased, while alkaline‐soluble fraction and nonprotein constituent (nonprotein nitrogen) content increased. Sugar exhibited stabilizing effect against denaturation of both sarcoplasmic and myofibrillar protein fractions. The water soluble protein with molecular weight of &gt;10 and 3–5 kDa was the main fraction, and progressive decrease of peptide fractions of &gt;10 kDa was observed during ripening process. Higher sugar levels showed protective effects against proteolysis of WSN and advantages on improving the textural characteristics. Samples with higher sugar levels had lower microbial counts in Cantonese sausage.PRACTICAL APPLICATIONSCantonese sausage is a traditional Chinese meat product that is well accepted by consumers over the world. The aim of this article was to evaluate the effect of sugar level on changes in physicochemical and biochemical characteristics, including chemical composition, proteolysis, textural profile and microorganism of Cantonese sausage during processing. The results will be favor of process control of reduced sugar Cantonese sausage production that consumers can enjoy as part of an ongoing healthier diet and lifestyle.

Effect of the length of salting time on the proteolytic changes in dry-cured lacón during ripening and on the sensory characteristics of the final product

The effects of the length of salting time (0.75, 1 or 1.25days/kg) on the proteolytic changes that take place during ripening of dry-cured lacón (a traditional meat product made in NW Spain) and on the sensory characteristics of the final product were investigated.The rate of proteolysis decreased as the length of salting time was increased. The salting time did not affect the free amino acid profile, which appears to indicate that the same enzymatic activities occurred during ripening of all batches of lacón, and that the length of salting time modulated these activities.Longer salting times resulted in a more intense yellow colour of the fat, a more intense red colour of the meat and harder meat, as well as more rancid odour, and more intense salty, cured and rancid taste of the dry-cured lacón pieces. Regarding the global evaluation, the tasters preferred the pieces that had been salted for an intermediate length of time (1day/kg).

Scanning electron microscopy analysis of erythrocytes in thromboembolic ischemic stroke

Erythrocytes play an important role in hemostasis and disease conditions. During ischemic stroke, erythrocytes undergo oxidative and proteolytic changes resulting in a changed cellular rheology. Blood samples were obtained from controls and thromboembolic ischemic stroke patients (within 48 h of stroke). The ultrastructure of erythrocytes was compared, using a scanning electron microscope (SEM). Abnormal morphology included codocytes, knizocytes, stomatocytes, and echinocytes. Percentage of abnormal cells was calculated, and the analyses were performed using the statistical program NCSS with the level of significance set at 0.05. A t-test was carried out to compare the data from the erythrocyte counts of stroke patients with that of the control subjects. Ultrastructural SEM results showed that there are a large percentage of erythrocytes in healthy individuals that do not have a typical discoid shape, when studying the cells using a high magnification electron microscope. Furthermore, analysis showed that variation in shape is so subtle that it is not clearly visible using a typical light microscopy blood smear analysis. Thromboembolic ischemic stroke patients presented with a significant amount of erythrocytes with abnormal morphology. We suggest that in healthy individuals, a typical smear would contain several nondiscoid-shaped erythrocytes, only clearly visible at high magnification. However, thromboembolic ischemic stroke does significantly impact erythorcyte shape, and this change in morphology may result in an impaired microcirculation, as well as impaired oxygen carrying capacity. This changed morphology may further complicate the restoring of homeostasis caused by acute thromboembolic stroke.

PROTEOLYTIC CHANGES DURING PROCESSING IN TURKISH DRY‐CURED MEAT PRODUCT (PASTIRMA) WITH DIFFERENT SALT LEVELS

ABSTRACTThe effects of different salt (NaCl) contents on proteolytic changes during processing in the dry‐cured meat product pastırma were investigated. Pastırma samples were produced with three different NaCl levels (3, 6 and 9%) and proteolytic changes were monitored.A progressive increase in nonprotein nitrogen (NPN) and free amino acids (FAAs) was detected during processing. High‐salt pastırma samples had the highest FAAs. Drying and pressing stages before pasting with çemen resulted in a decrease in water‐soluble nitrogen (WSN) and a slight increase in NPN and FAA. High salt level and processing time resulted in the accumulation of FAAs. The increase in WSN, NPN and FAA contents after çemen treatment indicated that the çemen used in the pasting process had an impact on accumulation of these components in pastırma. However, no significant effect of salt level was observed on WSN and NPN. Sarcoplasmic proteins decreased considerably after salting due to drainage. Myofibrillar proteins degraded during processing, particularly in samples with 6 and 9% NaCl.PRACTICAL APPLICATIONSProteolysis is one of the most important biochemical changes occurring during the processing of dry‐cured meat products such as ham or pastırma. The effect of additional salt concentrations and processing stages on proteolysis in Turkish dry‐cured meat product, pastırma, was studied during processing. Processing stages (salting, drying, pressing and pasting with çemen mixture) resulted in increases in NPN and FAA contents. High salt level (9% NaCl) and processing stages, particularly pasting with çemen mixture, facilitated the accumulation of FAA. Salting resulted in denaturation or insolubilization of proteins. Insolubilization of sarcoplasmic proteins was clearly seen in samples with 6 and 9% NaCl, depending on increased salt concentration during processing. In contrast, myofibrillar proteins in samples with 6 and 9% NaCl degraded during processing. From these results, processing conditions (salt concentration of pastırma and pasting with çemen) can determine the compounds released from protein breakdown during processing.

Effect of Proteolysis and Calcium Equilibrium on Functional Properties of Natural Cheddar Cheese during Ripening and the Resultant Processed Cheese

The changes in proteolysis, calcium (Ca) equilibrium, and functional properties of natural Cheddar cheeses during ripening and the resultant processed cheeses were investigated. For natural Cheddar cheeses, the majority of the changes in pH 4.6 soluble nitrogen as a percentage of total nitrogen (pH 4.6 SN/TN) and the soluble Ca content occurred in the first 90 d of ripening, and subsequently, the changes were slight. During ripening, functional properties of natural Cheddar cheeses changed, that is, hardness decreased, meltability was improved, storage modulus at 70 °C (G'T=70) decreased, and the maximum tan delta (TDmax) increased. Both pH 4.6 SN/TN and the soluble Ca were correlated with changes in functional properties of natural Cheddar cheeses during ripening. Kendall's partial correlation analysis indicated that pH 4.6 SN/TN was more significantly correlated with changes in hardness and TDmax. For processed cheeses manufactured from natural Cheddar cheeses with different ripening times, the soluble Ca content did not show significant difference, and the trends of changes in hardness, meltability, G'T=70, and TDmax were similar to those of natural Cheddar cheeses. Kendall's partial correlation analysis suggested that only pH 4.6 SN/TN was significantly correlated with the changes in functional properties of processed cheeses.

Lipolysis, proteolysis and sensory characteristics of a Spanish fermented dry-cured meat product (salchichón) with oregano essential oil used as surface mold inhibitor

The superficial antifungal activity of oregano essential oil (OEO) in Spanish fermented dry-cured sausages (“salchichón”), and its effects on lipolysis, proteolysis and sensory characteristics were evaluated. The surface application of OEO reduced mold contamination on the surface, without significantly affecting the drying process. To evaluate the intensity of lipolysis during the ripening process, the profile and content of free fatty acids were determined. The addition of OEO led to a higher amount of unsaturated fatty acids, but lipolysis was not greatly affected. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which was used to qualitatively assess the proteolytic changes in the sarcoplasmic and myofibrillar proteins during the process, pointed to very similar patterns in all the sausages. OEO did not significantly affect the sensory properties, but increased hardness, resulting in a better texture. Therefore, a shorter ripening time may be necessary for sausages treated with OEO.

Production of peptides and free amino acids in a sterile extract describes peptidolysis in hard-cooked cheeses

Hard cooked cheeses are mostly manufactured with lactic starters of Lactobacillus helveticus, which constitute a major proteolytic agent in the food. In this work, we assessed the proteolysis produced by enzymes of two strains of L. helveticus in a new cheese model, which consisted of a sterile substrate prepared with hard-cooked cheeses, and identified the time of ripening when main changes in proteolysis are produced. The extract, a representative model of the aqueous phase of the cheeses, was obtained from Reggianito cheeses of different ripening times (3, 90, and 180 days) made with starters composed of the strains tested, either SF138 or SF209. To obtain the substrate, the cheese was extracted with water, then centrifuged and the aqueous phase was sterilized by filtration through membrane (0.45 μm). The substrates were incubated at 34 °C during 21 days; samples were taken at 0, 3, 7, 14, and 21 days. Sterility was verified by plating samples on skim milk agar and incubating at 37 °C for 48 h. Proteolysis was determined by liquid chromatography of soluble peptides and free amino acids. Great variation in peptide profiles was found as incubation progressed in cheese extracts, which evidenced that proteases and peptidases from the starter were active and able to degrade the proteinaceous material available in the extracts. The extracts derived from cheeses with L. helveticus SF138 showed low production of peptides and a notable increase in free amino acids content during incubation. L. helveticus SF209, on the contrary, caused an increase on soluble peptides, but the free amino acids accumulation was lower than in the first case, which suggested that L. helveticus SF209 had either a low peptydolitic activity or produced an intense amino acids breakdown. This trend was more evident for extracts prepared with 90-day-old cheeses. It was concluded that the strains of L. helveticus assayed showed potentially complementary proteolytic abilities, as SF209 was able to provide a continuous replenishment of peptides during incubation, while SF138 increased their hydrolysis to free amino acids. The extract was an appropriate medium to model hard cooked cheese ripening in short periods of time.

Researches Regarding the Dynamics of some Proteolytic Changes in Beef and Pork during the Storage in Refrigerated or Frozen Form

The proteolytic changes in beef and pork during the storage in refrigerated or frozen form have been monitored in order to optimize the storage time and temperatures in storage rooms.

Researches Regarding the Dynamics of some the Proteolytic Changes in Meat Products during Preparation and Storage

During the thermal treatment meat and meat products suffer significant changes which lead to the improvement of their organoleptic proprieties (texture, colour, flavour), of their digestibility and to the increase of the digestive use ratio. By heating of meat there occur physical and chemical changes of the muscular proteins which, in their turn, have an influence on the water retention capacity, pH value and ions redistribution. Following to the thermal treatment up to 100 C the most important changes occur in proteins which are denaturised. The denaturation process leads to a structural change of proteins but preserves their integrity and respectively their molecular weight. There have been performed physical and chemical analyses in order to assess the progress of proteolysis on 10 samples of sausage (brand name: Cârnaţi trandafir) and 10 samples of salami (brand name: Salam de vara), during fabrication and storage at 10-12° C up to their expiry date. There have been assessed: the water content, pH value, total nitrogen, proteins content, ammoniacal nitrogen content and the protein splitting rates by standardized methods. During the fabrication of meat products the pH value changes in accordance with the fabrication phase and with the proteolytic changes suffered by meat, half-finished products, filling paste and the final product in a range from 5.85 up to 5.93 and from 6.11 to 6.23 during the storage. During the fabrication and storage as final product, the water content decreases from 68.3 to 49.5 %. The total nitrogen content decreases during the fabrication and storage from 54.9 to 53.1 for the sausage brand Cârnaţ Trandafir and from 52.9 to 49.5 % for the salami brand Salam de vara. There has been recorded a proportional decrease of the proteins content. The ammoniacal and urea nitrogen moderately increase up to the delivery and intensively during the storage. The value of the protein splitting rates changes proportionally with the values of urea and ammoniacal nitrogen and in inverse ratio to the total nitrogen content. The proteolytic activity is not highlighted during the thermal treatment process due to the inactivation of some proteolytic enzymes but after fabrication and during the storage the proteolytic activity increases and is characterized by a decrease of total nitrogen and an increase of urea and ammoniacal nitrogen and of the proteins splitting rates.