A practical reference on protease: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-24. Anything still debated is marked as such rather than presented as settled.
Whey protein hydrolysate appears in infant formula, sports nutrition, and clinical nutrition. In infant formula, extensively hydrolyzed products are used when a reduced allergenicity is desired, though not all hydrolysates are hypoallergenic. In sports products, the ingredient is marketed for rapid amino acid delivery, but the practical advantage over intact whey protein remains debated. Research often compares hydrolysate with isolate or concentrate for absorption kinetics, muscle protein synthesis, and gastrointestinal tolerance. Regulatory categories differ by country, and label terms such as partially hydrolyzed or extensively hydrolyzed are defined in some jurisdictions but not others.
Whey protein hydrolysate is a dairy ingredient made by treating whey protein with proteolytic enzymes. The starting material is whey, the liquid remaining after cheese or casein production, and its main proteins include beta-lactoglobulin, alpha-lactalbumin, and bovine serum albumin. Enzyme action breaks peptide bonds, producing shorter peptides and some free amino acids. The result is not a single uniform substance; composition depends on whey source, enzyme type, hydrolysis conditions, and downstream filtration. Hydrolysates are often described by average peptide length or degree of hydrolysis rather than by one fixed molecular weight.
Compared with whey protein concentrate or isolate, hydrolysate has a smaller average peptide size and a higher proportion of low-molecular-weight fractions. This change can affect solubility, viscosity, osmolality, taste, and foam formation. Some hydrolysates are bitter because hydrophobic peptides are exposed during cleavage. The term hydrolysate does not indicate a guaranteed peptide profile; two products with the same reported hydrolysis value can differ in peptide sequence and residual intact protein. Commercial specifications usually state protein content, moisture, ash, fat, and microbiology, while peptide distribution may be reported as a range.
Quality control checks identity, composition, and contaminants. Moisture, ash, fat, and carbohydrate are measured by standard methods, and microbiological limits are set for total counts, coliforms, and specific pathogens. Heavy metals and pesticide residues may be monitored depending on market requirements. Adulteration with intact whey protein or individual amino acids is possible, so peptide fingerprints and free amino acid profiles can help verify authenticity. Regulatory frameworks vary: some countries treat hydrolyzed whey as a conventional dairy ingredient, while infant formula uses face additional compositional rules. Which marker peptides best confirm source and processing remains an open analytical question.
Storage stability depends on moisture, temperature, and packaging. Dry powders with low water activity resist microbial growth, but they can still absorb water, develop off-colors through Maillard reactions, or oxidize residual lipids. Sealed containers kept in a cool, dry place are standard. Stability studies typically monitor moisture, solubility, color, peptide size, and microbial counts over months. Established practice favors low humidity and moderate temperatures. How brief excursions above recommended conditions affect peptide profiles and sensory qualities is less predictable and may depend on the specific product matrix.
| Property | Value | Notes |
|---|---|---|
| Appearance | Off-white to light tan powder | Color can vary with hydrolysis and drying |
| Protein content | 70–90% dry basis | Lower if ash, lactose, or moisture remain |
| Degree of hydrolysis | Typically 5–35% | Partially and extensively hydrolyzed types differ |
| Solubility | Water-soluble | High across common food pH ranges, though peptide dependent |
| Common synonyms | Whey hydrolysate; hydrolyzed whey protein | Sometimes abbreviated WPH on labels |
Composition reflects the whey source and the extent of hydrolysis. Beta-lactoglobulin and alpha-lactalbumin fragments are common, and sweet whey may contribute glycomacropeptide. The amino acid profile remains broadly similar to intact whey protein, but peptide size affects how quickly nitrogen appears in blood after ingestion. Bitter notes often arise from short peptides with hydrophobic residues. Hydrolysates are used in sports nutrition, infant formula, and clinical nutrition, though effects on muscle, immunity, or allergy risk are separate research questions rather than guaranteed properties.
Whey protein hydrolysate is derived from whey, the liquid byproduct of cheese-making or casein coagulation. It consists of peptides and free amino acids produced when peptide bonds are cleaved by enzymes or acid. Hydrolysis lowers the average molecular weight and can change solubility, viscosity, and bitterness. The degree of hydrolysis indicates the proportion of peptide bonds broken and distinguishes partial from extensive hydrolysates. Commercial ingredients vary widely in peptide size, mineral content, and lactose level.
Physical properties such as particle size, bulk density, and reconstitution behavior affect handling and finished product quality. Water activity and moisture content influence shelf life; high moisture can promote caking, browning, and microbial growth. Color is monitored because Maillard reactions between peptides and reducing sugars can darken the powder during storage. Taste panels and instrumental methods may assess bitterness, which is a common challenge for hydrolysates. Specifications often include limits for heavy metals, microbiological counts, and residual fat, depending on the intended market.
Quality control for hydrolyzed whey protein focuses on composition, peptide size, and batch consistency. Protein content is commonly measured by Kjeldahl or combustion analysis, while moisture and ash are determined by gravimetric methods. Peptide molecular weight distribution is often assessed by size exclusion chromatography or mass spectrometry. The extent of hydrolysis can be estimated by titration, trinitrobenzenesulfonic acid assays, or formol titration. Because hydrolysis produces a complex mixture, no single test captures every relevant property, and laboratories often combine several methods.
A lack of accurate data makes it difficult to document numerically the extent of the human losses suffered by Polish citizens during World War II. Additionally, many assertions made in the past must be considered suspect due to flawed methodology and a desire to promote certain political agendas. The last available enumeration of ethnic Poles and the large ethnic minorities is the Polish census of 1931. Exact population figures for 1939 are therefore not known. According to the United States Holocaust Memorial Museum, at least 3 million Polish Jews and at least 1.9 million non-Jewish Polish civilians were killed. According to the historians Brzoza and Sowa, about 2 million ethnic Poles were killed, but it is not known, even approximately, how many Polish citizens of other ethnicities perished, including Ukrainians, Belarusians, and Germans. Millions of Polish citizens were deported to Germany for forced labor or to German extermination camps such as Treblinka, Auschwitz and Sobibór. Nazi Germany intended to exterminate the Jews completely, in actions that have come to be described collectively as the Holocaust. The Poles were to be expelled from areas controlled by Nazi Germany through a process of resettlement that started in 1939. Such Nazi operations matured into a plan known as the Generalplan Ost that amounted to displacement, enslavement and partial extermination of the Slavic people and was expected to be completed within 15 years.
The Ehrlich pathway refers to this process in which alpha-keto acids are decarboxylated and transformed to aldehydes and to higher alcohols. The temperature of the fermentation process also greatly affects the alcohol content of the resulting product. For example, a study conducted by Pinal et al. found that cultivating two strains at a temperature of 35 °C as compared to a temperature of 30 °C produced more isoamyl alcohol. The higher temperature appears to be favorable for the action of the yeast. The age of the agave plant is also a factor: the older the plant, the greater the production of higher-order alcohols. It was shown in a study that the concentration of amyl alcohol increased by 30% as the plant aged. Conversely, a higher concentration of methanol is found when using younger plants. This change may be due to differences in agricultural practices with plants of different ages.
== Disadvantages == A disadvantage to MIKES is that observations are made later in the ion flight path when compared to other methods. Also, a smaller number of ions will typically decompose. This will in turn cause the sensitivity to be lower than other kinetic energy spectroscopy methods.
=== Selective pressure incorporation (SPI) method for production of alloproteins === There have been many studies that have produced protein with non-standard amino acids, but they do not alter the genetic code. These protein, called alloprotein, are made by incubating cells with an unnatural amino acid in the absence of a similar coded amino acid in order for the former to be incorporated into protein in place of the latter, for example L-2-aminohexanoic acid (Ahx) for methionine (Met). These studies rely on the natural promiscuous activity of the aminoacyl tRNA synthetase to add to its target tRNA an unnatural amino acid (i.e. analog) similar to the natural substrate, for example methionyl-tRNA synthase's mistaking isoleucine for methionine. In protein crystallography, for example, the addition of selenomethionine to the media of a culture of a methionine-auxotrophic strain results in proteins containing selenomethionine as opposed to methionine (viz. Multi-wavelength anomalous dispersion for reason). Another example is that L-photo-leucine and photomethionine are added instead of leucine and methionine to cross-label protein. Similarly, some tellurium-tolerant fungi can incorporate tellurocysteine and telluromethionine into their protein instead of cysteine and methionine. The objective of expanding the genetic code is more radical as it does not replace an amino acid, but it adds one or more to the code. On the other hand, proteome-wide replacements are most efficiently performed by global amino acid substitutions.
Sources: en.wikipedia.org
== Uses in sintering == The sintering process is taking a powder, putting it into a mold and heating it to below its melting point. Sintering is based on atomic diffusion, the atoms in the powder particle diffuse into surrounding particles eventually forming a solid or porous material. It has been discovered that Li2TiO3 powders have a high purity and good sintering ability.
Additionally, beta-cell function has to be interpreted in light of the prevailing insulin sensitivity. This is necessary since the beta cell mass is adjusted as required by dynamical compensation, giving rise to a hyperbolic relationship between insulin sensitivity and beta cell function. In the state of insulin resistance beta cells proliferate and their secretory capacity subsequently rises. One possibility to address this relation is to resort to a normalization of beta cell function based on a disposition metric. The disposition index, calculated as product of insulin sensitivity and beta cell function, is assumed to be a constant during the development of insulin resistance. It is generally assumed that the glucose tolerance of an individual is related to the disposition index. In this model, different values of glucose tolerance are represented by different hyperbolas, so that within one hyperbola the product of insulin sensitivity and beta cell function remains a constant. In summary, to provide a meaningful mechanistic explanation of insulin-glucose homeostasis, beta cell function and insulin sensitivity have to be assessed simultaneously and it is necessary to interpret all observations in the context of insulin sensitivity or resistance.
== External links == PROK1+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH) PROK2+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
=== Protein stabilization for optimized isolation === Thermofluor pre-screens can be performed that sample a wide range of pH, ionic strength, and additives such as added metal ions and cofactors. The generation of a protein response surface is useful for establishing optimal assay conditions and can frequently lead to improved purification scheme as required to support HTS campaigns and biophysical studies.
== Pseudomonas syringae as a model system == Owing to early availability of genome sequences for P. syringae pv. tomato strain DC3000, P. syringae pv. syringae strain B728a, and P. syringae pv. phaseolicola strain 1448A, together with the ability of selected strains to cause disease on well-characterized host plants such as Arabidopsis thaliana, Nicotiana benthamiana, and tomato, P. syringae has come to represent an important model system for experimental characterization of the molecular dynamics of plant-pathogen interactions. The P. syringae experimental system has been a source of pioneering evidence for the important role of pathogen gene products in suppressing plant defense. The nomenclature system developed for P. syringae effectors has been adopted by researchers characterizing effector repertoires in other bacteria, and methods used for bioinformatic effector identification have been adapted for other organisms. In addition, researchers working with P. syringae have played an integral role in the Plant-Associated Microbe Gene Ontology working group, aimed at developing gene ontology terms that capture biological processes occurring during the interactions between organisms, and using the terms for annotation of gene products.
Sources: en.wikipedia.org
She collaborated with the company again in February 2025, to promote the "Cherry Crush Zero Sugar" flavour, in which she and Jedward attempted a Guinness World Record to see how many post-it notes they could attach to her within a minute. The attempt, which was overseen by an adjudicator, saw them attach 30, failing to break the record of 70.
Netter, Frank H. (1987), Musculoskeletal system: anatomy, physiology, and metabolic disorders, Summit, New Jersey: Ciba-Geigy Corporation Jaffe, N.; et al. (2009). Pediatric and Adolescent Osteosarcoma. New York: Springer. ISBN 978-1-4419-0283-2.
Derek Malcolm of the Evening Standard felt that the movie was a "dim reworking of Fatal Attraction" and noted: "Larter as the pathological minx is the best thing about it." Obsessed opened No. 1 in its opening weekend with $28 million, and making a total domestic gross of $68 million, becoming Larter's second highest-grossing film in North-America. Larter was nominated for a third time for a Teen Choice Award when she and Beyoncé were nominated for the Teen Choice Award for Choice Movie: Rumble at the 2009 Teen Choice Awards and an MTV Movie Award for Best Fight both for Obsessed. Larter reprised her role of Claire Redfield in Resident Evil: Afterlife (2010), which was filmed in 3D and saw her character ambushed and mentally manipulated by the fictional Umbrella Corporation, before she is rescued by Alice (Milla Jovovich). Like the previous Resident Evil entries, the film received negative reviews but became a major commercial success, earning $296 million worldwide. On returning to the role of Claire, Larter told JoBlo.com: "I guess people liked me as her... I'm excited that they brought me back... to work with the man [Paul W. S. Anderson] who really created this world and this vision was what excited me about joining this next installment". In 2010, Larter appeared as the title character in a short film for Absolut Vodka entitled "Lemon Drop". After the release of Afterlife, Larter went on hiatus to focus on her family.
== LLFP radioactivity compared == In total, the other six LLFPs, in thermal reactor spent fuel, initially release only a bit more than 10% as much energy per unit time as Tc-99 for U-235 fission, or 25% as much for 65% U-235+35% Pu-239. About 1000 years after fuel use, radioactivity from the medium-lived fission products Cs-137 and Sr-90 drops below the level of radioactivity from Tc-99 or LLFPs in general. (Actinides, if not removed, will be emitting more radioactivity than either at this point.) By about 1 million years, Tc-99 radioactivity will have declined below that of Zr-93, though immobility of the latter means it is probably still a lesser hazard. By about 3 million years, Zr-93 decay energy will have declined below that of I-129. Nuclear transmutation is under consideration as a disposal method, primarily for Tc-99 and I-129 as these both represent the greatest biohazards and have the greatest neutron capture cross sections, although transmutation is still slow compared to fission of actinides in a reactor. Transmutation has also been considered for Cs-135, but is almost certainly not worthwhile for the other LLFPs. Given that stable caesium-133 is also produced in nuclear fission and both it and its neutron activation product 134Cs are neutron poisons, transmutation of 135Cs might necessitate isotope separation. 99Tc is particularly attractive for transmutation not only due to the undesirable properties of the product to be destroyed and the relatively high neutron absorption cross section but also because 100Tc rapidly beta decays to stable 100Ru.
=== Contact freeze dryers === Contact freeze dryers use contact (conduction) of the food with the heating element to supply the sublimation energy. This type of freeze dryer is a basic model that is simple to set up for sample analysis. One of the major ways contact freeze dryers heat is with shelf-like platforms contacting the samples. The shelves play a major role as they behave like heat exchangers at different times of the freeze-drying process. They are connected to a silicone oil system that will remove heat energy during freezing and provide energy during drying times. Additionally, the shelf-fluid system works to provide specific temperatures to the shelves during drying by pumping a fluid (usually silicone oil) at low pressure. The downside to this type of freeze dryer is that the heat is only transferred from the heating element to the side of the sample immediately touching the heater. This problem can be minimized by maximizing the surface area of the sample touching the heating element by using a ribbed tray, slightly compressing the sample between two solid heated plates above and below, or compressing with a heated mesh from above and below.
Sources: en.wikipedia.org
It is made from whey, the liquid byproduct of cheese or casein manufacture. The whey protein is treated with enzymes that cleave peptide bonds. The resulting mixture contains peptides of varying lengths plus some free amino acids.
Whey protein isolate is largely intact protein with a high protein content by dry weight. Hydrolysate has been enzymatically broken into smaller peptides, which can change taste, osmolality, and absorption behavior. Both can have similar total amino acid content, but their peptide profiles differ.
No. Hypoallergenic status depends on the extent of hydrolysis and the residual allergenic protein fragments. Regulatory bodies set specific criteria for products labeled hypoallergenic or extensively hydrolyzed. A hydrolysate not meeting those criteria may still contain allergenic epitopes.
Common laboratory methods measure free amino groups with TNBS or OPA reagents. The result is converted to a percentage using a reference standard and a defined protocol. Values are method-dependent, so comparisons require the same assay conditions.