Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.9 (enterokinase)
 675 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activation mechanism of pancreatic enzymes refluxing into the biliary tract in the anomalous arrangement of pancreaticobiliary ducts (APBD) remains unclear. In order to elucidate this activation mechanism, an immunohistochemical examination of both bile ducts and gallbladders was carried out on 20 patients with APBD to determine whether or not enterokinase (EK) producing cells exist in the biliary tract, by employing an avidin-biotin-peroxidase complex (ABC) method using a monoclonal antibody, hek-1. Immunoreactive EK was found in the metaplastic epithelium of the bile duct in 2 patients and the gallbladder in one, suggesting that EK production at the metaplastic epithelium is involved in an activation mechanism of pancreatic enzymes refluxing into the biliary tract. The same study was performed on the gallbladders of 62 patients without APBD, which revealed immunoreactive EK in some parts of the metaplastic epithelium of the gallbladder in 2 patients. Thus, in cases of pancreatic juice refluxing into the biliary tract regardless of the presence of APBD, we can not refute the possibility that refluxed pancreatic enzymes may be at least partly activated by EK produced at the metaplastic epithelium.
 ...
PMID:Immunohistochemical studies on enterokinase producing cells in the biliary tract. 178 6

Immunoassays are representative biochemical detection methods. Among them, sandwich-type immunoassays, typified by sandwich ELISA, have used in disease diagnosis or biochemical detection with high target selectivity. Horseradish peroxidase and alkaline phosphatase have been typically used for signal amplification in ELISA. Recently developed sandwich-type immunoassays such as biobarcode immunoassays, immuno-PCR, and immuno-RCA have improved sensitivity by changing mainly the signal amplification method. To develop a novel amplification method in ELISA, an enzyme-cascading system was incorporated into an ELISA, and the new assay is termed a cascading enzyme-linked immunosorbent assay (CELISA). This CELISA includes a trypsinogen-enterokinase combination as the cascading enzyme system, and was used to detect alpha-fetoprotein (AFP), which is a liver cancer marker, and prostate-specific antigen (PSA). Using a colorimetric reagent for signal generation, CELISA had 0.1-10pM limits-of-detection for AFP and PSA in whole human serum and assay buffers, depending on the platform, well plate, or microbead type used. This study represents the first example that incorporated an enzyme cascading step in an ELISA system, resulting in successful signal amplification with sensitive detection of pathogenic antigens in serum.
 ...
PMID:Cascade enzyme-linked immunosorbent assay (CELISA). 1966 63

Encapsulation of active proteins in the hydrophilic core of vesicular liposomes is important for developing a therapeutic protein carrier system. The efficiency of liposomal encapsulation of proteins is generally low. A better understanding of the fundamental mechanisms of encapsulation is needed to increase this efficiency. In this study we investigated the effects of operating parameters such as phospholipid concentration, buffer pH and ionic strength, protein size and surface charge, and liposome size on the enzyme encapsulation yield. Four model enzymes of different molecular weights and isoelectric points (trypsin, horseradish peroxidase, enterokinase and hyaluronidase) were encapsulated into three different sized liposomes (125 nm, 194 nm, and 314 nm in mean diameter). Relatively inert and neutral DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) was used as the main phospholipid in the liposomes. Size exclusion chromatography was used to separate the enzyme-encapsulated liposomes from the free enzyme, and the encapsulation yield was determined from the peak area. The encapsulation yield was generally low ranging from ca. 5% to 20%, and did not depend much on the molecular weight of the enzyme encapsulated. Larger liposomes had higher encapsulation yields. The electrostatic interaction between the phospholipid and enzyme was the most significant parameter in determining the encapsulation yield. Thus adjusting buffer pH and ionic strength and adding charged phospholipids to the liposome preparation to impart electric charge to the lipid bilayer could significantly improve the yield. This approach can be used to optimize the liposomal encapsulation of clinically significant proteins.
 ...
PMID:Effects of operating parameters on the efficiency of liposomal encapsulation of enzymes. 2239 67