Nutrition Guide

TPSAB1
TPSB2
TPSD1
TPSG1

Tryptase is the most abundant secretory granule-derived serine proteinase contained in mast cells that has recently been used as a marker for mast cell activation. It is involved with allergenic response and is suspected to act as a mitogen for fibroblast lines. Elevated levels of serum tryptase occur in both anaphylactic and anaphylactoid reactions, but a negative test does not exclude anaphylaxis.

Recombinant tPA is used in diseases that feature blood clots, such as pulmonary embolism, myocardial infarction and stroke. To be effective, tPA must be administered within the first three hours of the event to be given intravenously, or within six hours to be administered through an arterial catheter directly to the site of occlusion. The guideline in Ontario, Canada hospitals for ischemic strokes is that tPA must be given within 3 hours of the onset of symptoms. Because of this, only about 3% of patients qualify for this treatment. tPA appears to show benefit not only for large artery occlusions but also for lacunar strokes. Since tPA dissolves blood clots, there is risk of hemorrhage with its use.

Recently tPA has been used to dissolve thrombi associated with ischemic strokes and brain injury.

In addition, people with frostbite that were treated with tPA had fewer amputations than those that were not.[1]

Tissue plasminogen activator is a protein encoded by the PLAT gene, which is located on chromosome 8. The primary transcript produced by this gene undergoes alternative splicing, producing three distinct messenger RNAs.

The classic role of tPA is in the clotting system. Specifically, tPA catalyzes the conversion of plasminogen into plasmin. It does so by cleaving the single-chained plasminogen into two chains. These two chains are linked by a disulfide bond and the resulting molecule is called plasmin.

Increased enzymatic activity causes hyperfibrinolysis, which manifests as excessive bleeding. Decreased activity leads to hypofibrinolysis which can result in thrombosis or embolism.

Tissue plasminogen activator also plays a role in cell migration and tissue remodeling.

Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. Specifically, it is a serine protease (EC 3.4.21.68) found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown. Because it works on the clotting system, tPA is used in clinical medicine to treat stroke.

Proteinase K (also protease K or endopeptidase K) EC 3.4.21.64 is a broad-spectrum serine protease. The enzyme was discovered in 1974 in extracts of the fungus Engyodontium album (formerly Tritirachium album).[1] Proteinase K is able to digest native keratin (hair), hence, the name “Proteinase K”. The predominant site of cleavage is the peptide bond adjacent to the carboxyl group of aliphatic and aromatic amino acids with blocked alpha amino groups. It is commonly used for its broad specificity.

Proteinase K is commonly used in molecular biology to digest protein and remove contamination from preparations of nucleic acid. Addition of proteinase K to nucleic acid preparations rapidly inactivates nucleases that might otherwise degrade the DNA or RNA during purification. It is highly-suited to this application since the enzyme is active in the presence of chemicals that denature proteins, such as SDS and urea, chelating agents such as EDTA, sulfhydryl reagents, as well as trypsin or chymotrypsin inhibitors. Proteinase K is also stable over a wide pH range (4-12), with a pH optimum of pH 7.5-12.[1]

The enzyme’s activity towards native proteins is stimulated by denaturants such as SDS. In contrast, when measured using peptide substrates, denaturants inhibit the enzyme. The reason for this result is that the denaturing agents unfold the protein substrates and make them more accessible to the protease.[2]

Proteinase 3 is a serine protease enzyme expressed mainly in neutrophil granulocytes. Its exact role in the function of the neutrophil is unknown. It is also the epitope of anti-neutrophil cytoplasmic antibodies (ANCAs) of the cANCA (cytoplasmic subtype) class, a type of antibody frequently found in the disease Wegener’s granulomatosis.

PSA was first identified by researchers attempting to find a substance in seminal fluid that would aid in the investigation of rape cases.[21] PSA is now used to indicate the presence of semen in forensic serology[22]. The semen of adult males has PSA levels far in excess of those found in other tissues, therefore, a high level of PSA found in a sample is an indicator that semen may be present. Because PSA is a biomarker that is expressed independently of spermatazoa, it remains useful in identifying semen from vasectomized and azoospermic males.[23]

It is important to note that PSA can also be found at low levels in other body fluids, such as urine and breast milk, thus setting a high minimum threshold of interpretation to rule out false positive results is necessary to conclusively state that semen is present.[17] While traditional tests such as crossover electrophoresis have a sufficiently low sensitivity to only detect seminal PSA, newer diagnostics tests developed from clinical prostate cancer screening methods have lowered the threshold of detection down to 4ng/mL.[24] This level of antigen has been shown to be present in the peripheral blood of males with prostate cancer, and rarely in female urine samples and breast milk.[17] No studies have been performed to assess the PSA levels in the tissues and secretions of pre-pubescent children. Therefore, the presence of PSA from a high sensitivity (4ng/mL) test cannot conclusively identify the presence of semen, so care must be taken with the interpretation of such results.

The U.S. Food and Drug Administration (FDA) has approved the PSA test for annual screening of prostate cancer in men of age 50 and older. PSA levels between 4 and 10 ng/mL (nanograms per milliliter) are considered to be suspicious and should be followed by rectal ultrasound imaging and, if indicated, prostate biopsy. PSA is false positive-prone (7 out of 10 men in this category will still not have prostate cancer) and false negative-prone (2.5 out of 10 men with prostate cancer have no elevation in PSA).[20] Recent reports indicate that refraining from ejaculation 24 hours or more prior to testing will improve test accuracy.[10]