Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We illustrate the use of polycrystalline silver halide fibers (2-20 microns transparency range) for attenuated total internal reflection Fourier transform infrared (IR) spectroscopic measurements of microsamples (10 micrograms of protein). A powerful adjunct technique is a simple method for carrying out deuterium for proton exchange. Spectra of trypsin, soybean trypsin inhibitor, and their complex are easily obtained. Two kinds of difference spectra (DS) are revealing: DS1 (changes in protein on combination with ligand), IR of the trypsin-soybean trypsin inhibitor complex (T.SBTI complex)--sigma [IR of trypsin (T) + IR of soybean trypsin inhibitor (SBTI)], the small values at all wavelengths indicating no conformational change of the proteins upon complexation, and DS2 (changes in materials on deuteration), IR of protioprotein--IR of deuterioprotein, which reveals the infrared bands affected by deuteration. The rate and the extent of the exchange are additional valuable parameters readily measured with this technique. In the present instance, the rate and the amount of the exchange for T.SBTI complex after 30 min was substantially less than that expected from the simple sum of the same parameters for the two individual proteins, T and SBTI. The enzymatic activity of trypsin on the fiber survived for more than a day, no autodegradation being detected by SDS-gel electrophoresis.
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PMID:Deuterium exchange on micrograms of proteins by attenuated total reflection Fourier transform infrared spectroscopy on silver halide fiber. 162 61

Recent observations in children with rotavirus gastroenteritis and in infant mice given rotavirus vaccine by oral administration suggest that this well-known gastrointestinal pathogen may infect the liver. To examine this possibility, the susceptibility of Hep G2 cells to infection with a variety of rotavirus strains was tested. These cells were used because they are considered to be well differentiated and exhibit many liver-specific functions. The Hep G2 cells supported the growth of the simian strain rhesus rotavirus (MMU 18006), a strain currently being used in vaccine trails, but did not support the growth of any human strain (D, DS1, Price or ST3). The rhesus rotavirus infection was cytopathic and resulted in release of lactate dehydrogenase. Rhesus rotavirus growth in Hep G2 cells displayed trypsin-enhanced infectivity and was inhibited by pretreatment of cells with Arthrobacter ureafaciens neuraminidase but not with neuraminidase from Clostridium perfringens. Hep G2 cells were also permissive for another simian strain (SA11), a bovine strain (UK) and single gene substitution reassortants containing VP7 (the major outer capsid neutralization protein) from a human rotavirus strain and the remaining 10 genes from either rhesus rotavirus or UK. In general, UK and its reassortants produced lower levels of antigen than did rhesus rotavirus and its reassortants. Hep G2 cells and other hepatic cell lines may prove to be useful tools to explore the hepatotropic potential of wild-type rotaviruses and candidate vaccine strains.
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PMID:Growth of group A rotaviruses in a human liver cell line. 217 Feb 64

The primary structure of the region in the outer layer protein VP3, containing the two sites associated with trypsin enhancement of infectivity of rotavirus was found to be greatly conserved in cultivable human rotavirus serotypes 1 (Wa), 2 (DS1), and 3 (P) and in four human rotaviruses directly purified from feces. Significant differences with this conserved sequence were found in human rotavirus serotype 4 (ST3), isolated from an asymptomatic neonate, and in seven animal rotaviruses. However, the two trypsin cleavage sites were conserved in every rotavirus VP3 sequence analyzed.
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PMID:Conservation in rotaviruses of the protein region containing the two sites associated with trypsin enhancement of infectivity. 301 4

The assignment of five disulfide bonds in the alpha subunit of human chorionic gonadotropin (hCG) using partial reduction and S-[14C]carboxymethylation has been reported earlier (Mise, T., and Bahl, O. P. (1980) J. Biol. Chem. 255, 8516-8522). Employing a similar approach, we have determined the locations of six disulfide bonds in hCG-beta. Two partially reduced and S-[14C]carboxymethylated hCG-beta derivatives, DS1.4-hCG-beta and DS3.4-hCG-beta in which on the average 1.4 and 3.4 disulfide bonds were modified, respectively, were prepared. The 14C-labeled derivatives were then completely reduced and S-carboxymethylated with nonradioactive iodoacetic acid and subjected to hydrolysis with trypsin. The radioactive peptides were purified by gel filtration and high voltage paper electrophoresis. The tryptic peptides containing two or more S-[14C]carboxymethylcysteines were further degraded using various proteolytic enzymes such as thermolysin, carboxypeptidase A and Y, cathespin C, and subtilisin to obtain individual S-[14C]carboxymethylcysteine-containing peptides. From the specific radioactivities of S-[14C]carboxymethylcysteines in DS3.4-hCG-beta, four out of six disulfide bonds, 9-90, 26-110, 34-88, and 93-100 were assigned. Similar data from DS1.4-hCG-beta gave the locations of the other two disulfide bonds, 23-72 and 38-57, while confirming the locations of four disulfide bonds derived from the radioactivity distribution in DS3.4-hCG-beta. Thus, all six disulfide bonds in hCG-beta have been located. The results of controlled reduction and S-[14C]alkylation also indicate that disulfide bond 93-100 is the most reactive, followed by disulfide bond 26-110, and that the least reactive among all is 34-88.
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PMID:Assignment of disulfide bonds in the beta subunit of human chorionic gonadotropin. 724 Feb 31