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protease

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A History of Protease Enzymes: From Early Physiological Observations to Modern Biochemistry

7 Décembre 2025, 18:23pm

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Publié par Box News

A History of Protease Enzymes: From Early Physiological Observations to Modern Biochemistry

Protease enzymes have a long, well-documented history that runs in parallel with the rise of modern biochemistry. The story begins in the 19th century with simple physiological observations about digestion and blood clotting and then accelerates in the 20th century as chemists and crystallographers proved that enzymes are real, isolable proteins and later worked out how proteases work at atomic detail.

The first protease to be recognized was pepsin, identified in 1836 by the German physiologist Theodor Schwann. Schwann observed that an acidic substance in gastric juice could dissolve proteinaceous food and he gave it the name “pepsin” (from the Greek for digestion), marking the first time a specific substance was associated with a chemical process of the body rather than with a living tissue as a whole. (Encyclopedia Britannica) Around the same period investigators were also noting that blood could be converted into a fibrous clot by an “enzymatic” action; Alexander Schmidt proposed in 1872 that an enzyme (which he called thrombin) converted fibrinogen to fibrin, an insight that set the stage for later work on the coagulation cascade. (MDPI)

The mid- to late-1800s saw further identification of digestive proteases. In 1876 the German physiologist Wilhelm Kühne isolated and named trypsin from pancreatic juice and helped popularize the term “enzyme” for these non-cellular ferments. Kühne’s work established that different organs produced distinct proteolytic activities with different chemical properties. (PMC)

Although pepsin, trypsin and related proteolytic activities were known for decades, a fundamental conceptual leap occurred in the early 20th century when enzymologists began to purify enzymes and to ask what enzymes actually were made of. James B. Sumner’s crystallization of urease in 1926 demonstrated that an enzyme could be obtained in crystalline form and behave like a pure chemical substance; Sumner concluded that enzymes were proteins, a result that was later reinforced when John H. Northrop crystallized pepsin, trypsin and chymotrypsin around 1929–1930. For this body of work Sumner, Northrop and Wendell Stanley were awarded the Nobel Prize in Chemistry in 1946. Those achievements moved enzymes — and proteases in particular — from physiological curiosities to definable molecular entities that could be studied chemically and structurally. (NobelPrize.org)

With purification and crystallization established, the mid-20th century concentrated on mechanism and structure. The serine proteases (trypsin, chymotrypsin, elastase and relatives) became model systems for enzymology, and in the 1960s crystallographers produced three-dimensional structures of chymotrypsin and related enzymes that revealed the classic “catalytic triad” and the oxyanion hole—key mechanistic features explaining how these proteins accelerate peptide-bond hydrolysis. At the same time, investigators refined systematic ways to describe protease specificity; the influential Schechter–Berger notation (introduced in 1967) standardized how cleavage sites and enzyme subsites are labeled (P1/P1′, S1/S1′ etc.), which greatly helped comparative and mechanistic work. (PubMed)

Parallel threads of discovery broadened the protease story. Researchers characterized different catalytic classes (serine, cysteine, aspartic, and metalloproteases) and cataloged large protease families with distinct evolutionary origins and biological roles. Work on blood coagulation in the first half of the 20th century mapped a cascade of proteolytic activations (many involving zymogens, inactive precursors that are activated by proteolysis), which explained how a single enzymatic trigger can be amplified into clot formation and later regulated by specific inhibitors. (PubMed)

Clinical and genetic findings also shaped protease biology. During the 20th century the discovery of endogenous protease inhibitors and their deficiencies—most notably alpha-1 antitrypsin (AAT) deficiency linked to early-onset emphysema—illustrated how an imbalance between proteases and their inhibitors causes disease and focused attention on protease regulation as medically important. Advances in molecular genetics, protein chemistry and later recombinant methods in the 1970s–1990s expanded both the list of known human proteases and the ability to manipulate them for therapy. (PubMed)

In recent decades protease research has become highly interdisciplinary. Structural biology, high-throughput substrate profiling, and genome sequencing revealed huge protease repertoires across life and clarified roles in immunity, development, cancer, and pathogen biology. Proteases are now both laboratory tools and clinical agents: they serve as diagnostic markers, therapeutic targets (for example in clotting disorders, hepatitis C protease inhibitors, and cancer), and, in some cases, as administered enzymes for replacement therapy or wound debridement. Contemporary reviews and historical retrospectives highlight how an observation about “something in stomach juice” in 1836 grew into a molecular field that underpins major areas of physiology and medicine. (PubMed)

Taken together, the history of proteases illustrates a classic arc in life-science discovery: descriptive physiology gave names and phenomena in the 19th century; purification and proof that enzymes are proteins took place in the early 20th century; structural and mechanistic understanding arrived in the mid-20th century; and molecular, genetic, and therapeutic applications have followed in the late 20th and early 21st centuries.

(Source : ChatGPT)

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Protease Enzymes: Biological Functions and Therapeutic Implications

7 Décembre 2025, 17:08pm

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Publié par Box News

Protease Enzymes: Biological Functions and Therapeutic Implications

Protease enzymes are proteins that act like tiny molecular scissors: they cut other proteins into smaller pieces. In biological terms, a protease recognizes specific links — peptide bonds — that join amino acids together in a protein, and it breaks those links. That breaking is not random; each protease has preferences for where it cuts, and that specificity is what lets the cell control when and where proteins are activated, recycled, or removed.

There are several main families of proteases, named for the chemistry of the cut they perform. Serine proteases, like trypsin and chymotrypsin, use a serine amino acid in their active site to do the cutting. Cysteine proteases use a cysteine residue, aspartic proteases use an aspartic acid, and metalloproteases need a metal ion (usually zinc) to work. Those biochemical differences determine each enzyme’s shape, where it functions (acidic stomach, neutral blood, inside cells, or outside tissues), and which protein targets it prefers.

Proteases play dozens of essential roles in the body. In digestion, stomach and pancreatic proteases (for example pepsin in the stomach, and trypsin/chymotrypsin from the pancreas) break dietary proteins into amino acids and short peptides so the body can absorb and use them. Inside cells, proteases remove damaged or misfolded proteins and help recycle amino acids; this is fundamental for cell health. In the immune system and blood, proteases participate in cascades that help clot blood, fight infections, and clear debris — for example, the clotting and fibrinolysis systems use chains of protease activations to form or dissolve clots. Proteases also control programmed cell death (apoptosis) and tissue remodeling during growth, wound healing, and repair.

Because proteases regulate so many processes, their activity can produce important health benefits when functioning properly. Digestive proteases improve protein digestion and nutrient absorption; people with pancreatic insufficiency (such as some forms of chronic pancreatitis or cystic fibrosis) can regain nutrition and reduce symptoms when given pancreatic enzyme replacement therapy. Certain plant proteases, like bromelain (from pineapple) and papain (from papaya), have been studied for their anti-inflammatory and anti-swelling effects; some clinical trials suggest bromelain can reduce swelling and pain after surgery or injury. Topical proteases (for example collagenase) are used medically to remove dead tissue and help wounds heal by clearing away barriers so healthy tissue can grow. Other proteases — such as tissue plasminogen activator (tPA) — are important drugs because they break down dangerous blood clots in stroke and heart attack treatment. In short, proteases are both natural tools the body uses for maintenance and repair, and also useful therapeutic tools when given in controlled, medical settings.

Proteases are found in food and supplements as well as produced inside the body. Foods that naturally contain active proteases include fresh pineapple (bromelain) and papaya (papain), and fermentation or certain digestive enzyme supplements contain mixtures of proteases to help with digestion. In medicine, purified or recombinant proteases are formulated into pills, topical gels, or injected drugs for specific purposes such as enzyme replacement, wound debridement, or clot dissolution.

At the same time, proteases can cause harm if their activity is out of balance. Excessive protease activity can damage healthy tissue and worsen inflammation, and inappropriate protease activity is involved in diseases such as emphysema, some inflammatory conditions, and cancer progression. Protease-containing supplements can also interact with medications — notably blood thinners — and may cause stomach upset or allergic reactions in some people. Because commercial supplements are variably regulated, their potency and purity are not always guaranteed, so clinical use should be supervised by a health professional.

To sum up, protease enzymes are precision cutters of proteins that perform essential housekeeping, digestive, immune, and repair tasks in the body. When used or targeted appropriately, they offer real health benefits — from improving digestion to helping wounds heal and dissolving dangerous clots — but like any powerful biological tool, they must be used with care and clinical judgment. If you’re considering protease supplements or a medical protease treatment, it’s a good idea to discuss the potential benefits and risks with your healthcare provider so they can be matched to your specific needs.

(Source : ChatGPT)

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