Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Albumin Jaffna is an electrophoretically slowly moving genetic variant of human serum albumin found in two members of a Tamil family from Jaffna (Northern Sri Lanka), both heterozygous for the abnormal protein. Sequential analysis of albumin Jaffna, purified from serum by ion exchange chromatography on DEAE Sephadex and Mono Q columns, revealed that this variant is a new abnormal proalbumin, arising from a -1 Arg----Leu substitution, which prevents the proteolytic removal of the N-terminal hexapeptide and allows the mutated proalbumin to enter the circulation. The presence of two additional positive charges is in keeping with the decreased electrophoretic mobility of albumin Jaffna, as well as with its isoelectric point of 5.01, determined by chromatofocusing on a Mono P column. The variant is selectively cleaved by trypsin in vitro, leaving leucin -1 as N-terminal residue.
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PMID:A new proalbumin variant: albumin Jaffna (-1 Arg----Leu). 279 79

The activation of 14C-labeled estradiol by "true" and "pseudo" peroxidases to form conjugates and other products was compared in four model systems using H2O2, glutathione, Mn2+ or irradiated riboflavin. Albumin was used as acceptor except in the glutathione system. The binding of estradiol to glutathione in the presence of the true peroxidases, lacto- or uterine peroxidase (no H2O2 added), was also examined and the conditions shown to differ from those required with the pseudoperoxidases, microperoxidase or trypsin-digested cytochrome c. The conjugates were purified by chromatography after elution from Amberlite XAD-2 and the relative amounts of these products assessed by autoradiography. The ratio of steroid to glutathione in the main water-soluble metabolite formed with lactoperoxidase was found to be approx 1:1 in a double label experiment with [14C]estradiol and [3H]glutathione. It was also shown, using estradiol labeled with 3H in different positions of the steroid molecule, that lactoperoxidase acts non-specifically in catalyzing the formation of glutathionyl conjugates as indicated by the release of 3H2O. The possible role of peroxidase and glutathione in the metabolism of estrogens and in the formation of artifactual products is discussed.
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PMID:Metabolism of estradiol by true and pseudoperoxidases. 299 58

Affinity labeling with palmitic acid was used to identify long chain fatty acid-binding sites of bovine serum albumin. [1-14C]Palmitic acid was activated by esterification with N-ethyl-5-phenyl-isoxazolium-3'-sulfonate (Woodward's Reagent K). The product was purified by chromatography and shown to compete with unesterified fatty acids for binding sites on bovine serum albumin. Activated [14C]palmitic acid coupled covalently to albumin producing [14C]palmitoyl-albumins containing from 0.12 to a maximum of 6.9 mol of attached label per mol of albumin. The presence of the covalently attached affinity label depressed binding of other long chain fatty acids to albumin. Albumin carrying 1 eq. of [14C]palmitate was cleaved using cyanogen bromide, pepsin, and trypsin. Radioactive peptides were isolated by high pressure liquid chromatography. Three peptides accounted for greater than 90% of the label. Residues labeled with [14C]palmitate were identified as Lys-116, Lys-349 and Lys-473, and the relative distribution of label was 10, 45, and 45% respectively, consistent with the presence of two strong binding sites in the COOH-terminal half of albumin and a somewhat weaker site in the NH2-terminal half.
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PMID:Location of long chain fatty acid-binding sites of bovine serum albumin by affinity labeling. 309 94

In the various subcellular fractions of rat liver 45-75% of the total dolichol was esterified with a fatty acid. The esterification reaction was localized exclusively in the microsomes, and the transferase activity is 3-fold higher in the cation-insensitive smooth microsomes than in other microsomal subfractions. Although fatty acyl-CoAs tested served as substrates, palmitoyl-CoA was the most rapidly utilized. None of the phosphatidylcholine or phosphatidylethanolamine species tested could be utilized to esterify dolichol with a fatty acid, indicating the absence of transacylation. alpha-Saturated dolichols were esterified at a higher rate than their alpha-unsaturated counterparts. Albumin and low concentrations of Triton X-100 activated the esterification reaction, which was not dependent on mono- or divalent cations, ATP, or CoA. The sensitivity of the transferase activity to trypsin indicates localization of the enzyme(s) involved on the outer surface of microsomes (i.e. the cytoplasmic surface of the endoplasmic reticulum), as is also the case for enzymes of dolichol biosynthesis. Transferase activity was detected in all tissues examined but at a much lower level than in liver and testis. The patterns of fatty acids in dolichol esters of different organelles exhibited some specificity. Labeling in vivo indicated that esterification of dolichol may play a role in targeting this lipid from the endoplasmic reticulum to lysosomes.
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PMID:Esterification of dolichol in rat liver. 312 28

The possible role of lipoteichoic acid with respect to cell surface properties of Bifidobacterium bifidum subsp. pennsylvanicum was studied. Standard suspensions of bacteria were mixed with octane or xylene. B. bifidum subsp. pennsylvanicum was shown to possess a strongly hydrophobic cell surface. Hydrophobicity of the bacteria could be reduced by treatment with trypsin, pepsin (at pH 4.5), HCl and penicillin. The latter treatment resulted in an increased excretion of lipoteichoic acid. Albumin was capable of inhibiting the adherence to octane when it was present in the assay buffer. The data suggest that both protein and lipoteichoic acid may be involved in cell surface hydrophobicity. A great divergence in cell surface properties was observed within the genus Bifidobacterium.
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PMID:Cell surface hydrophobicity of Bifidobacterium bifidum subsp. pennsylvanicum. 409 36

Acetylsalicylic acid (aspirin) acetylates human serum albumin under physiologic conditions in vitro. These investigations were done to determine whether this phenomenon occurs in vivo and to delineate the site(s) of acetylation on the albumin molecule. Albumin was reacted in vitro with aspirin labeled with (14)carbon at the acetyl-1 or the carboxyl carbon. The altered albumin was hydrolyzed with trypsin and peptide mapping performed. Albumin so treated contains a unique peptide, designated "A," and shows diminution of two normal peptides, designated "B" and "C." Peptide "A" is never seen in normal albumin. Amino acid analyses indicate that peptide "A" equals the sum of peptides "B" and "C." Furthermore all three peptides contain lysine but lack arginine. Thus peptide "A" is formed by the acetylation of a lysine residue which is normally susceptible to trypsin and yields peptides "B" and "C." Radioautography of the peptide maps show most of the acetyl-1-(14)C activity in peptide "A." This indicates that one of the lysine residues in this peptide is the preferential site for the transacetylation reaction. Peptide "A," used as a marker for acetylation, is found in albumin from patients who take aspirin but is not demonstrable in albumin from one of these patients while she was taking sodium salicylate. A transacetylation reaction between aspirin and human albumin occurs in vivo and is similar to that observed in vitro.
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PMID:Structural changes in human serum albumin induced by ingestion of acetylsalicylic acid. 577 90

Primary cultures of liver cells isolated from adult rats by trypsin and collagenase perfusion techniques were carried out to compare cytologic and biochemical properties between the differently prepared cells. Trypsin-dispersed cells consisted of comparatively smaller cells, whereas collagenase-dispersed cells consisted of larger cells. The cell attachment efficiency on culture day 1 was about twice as high in the liver cells prepared with collagenase than those prepared with trypsin. Mature hepatocytes isolated by collagenase perfusion could be maintained in the primary culture for a longer period than those isolated by trypsin perfusion. Epithelial-like clear cells started to grow much earlier in the primary culture of the trypsin-dispersed liver cells than in that of the collagenase-dispersed liver cells. Earlier proliferation of epithelial-like clear cells could not be induced by in vitro trypsinization of the collagenase-dispersed liver cells. Both kinds of enzymatically prepared liver cells showed albumin production and exhibited glucose 6-phosphatase (D-glucose-6-phosphate phosphohydrolase, EC 3.1.3.9, G6Pase) and tyrosine aminotransferase (L-tyrosine: 2-oxoglutarate amino-transferase, EC 2.6.1.5, TAT) activities for 1 week in the primary culture. Albumin production was higher in the liver cells prepared with collagenase than those prepared with trypsin, whereas G6Pase activity was almost the same between them. TAT activity up to culture day 2 was about 3-fold higher in the liver cells prepared with collagenase than in those prepared with trypsin. Combined supplementation of dexamethasone (1 X 10(-5)M) and insulin (10 micrograms/ml) consistently improved the cell attachment efficiency and was very effective in the maintenance of mature hepatocytes in both types. Furthermore, these hormones enhanced the albumin production and TAT activity in both types.
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PMID:Comparison of cytologic and biochemical properties between liver cells isolated from adult rats by trypsin perfusion and those isolated by collagenase perfusion. 614 85

The protein binding of timegadine to albumin, serum, plasma and plasma enriched with the acute phase reactants alpha 1-acid glycoprotein, alpha 1-anti-trypsin and C-reactive protein was determined by equilibrium dialysis. The effects of other analgesic and anti-inflammatories (indomethacin, ketoprofen, paracetamol and sodium salicylate) and other basic drugs (disopyramide, lignocaine, propranolol and quinidine) on the binding of timegadine were also determined. Timegadine binding was concentration-dependent up to 0.5 micrograms/ml, but independent above this level up to 10.0 micrograms/ml, the mean and standard error being 93.8 +/- 0.5%. Albumin accounted for only 32.4% of timegadine bound to plasma. Plasma enrichment with the acute phase reactants led to significant increases in timegadine binding. Simultaneous dialysis with other drugs caused significant decreases in timegadine binding.
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PMID:The protein binding of timegadine determined by equilibrium dialysis. 650 87

[3H]Spiperone specific binding by microsomal membranes isolated from sheep caudate nucleus is decreased by trypsin and phospholipase A2 (Vipera russeli), but is insensitive to neuraminidase. The inhibitory effect of phospholipase A2 is correlated with phospholipid hydrolysis. After 15 min of phospholipase (5 micrograms/mg protein) treatment, a maximal effect is observed; the maximal lipid hydrolysis is about 56% and produces 82% reduction in [3H]spiperone binding. Equilibrium binding studies in nontreated and treated membranes showed a reduction in Bmax from a value of 388 +/- 9.2 fmol/mg protein before phospholipase treatment to a value of 52 +/- 7.8 fmol/mg protein after treatment, but no change in affinity (KD = 0.24 +/- 0.042 nM) was observed. Albumin washing of treated membranes removes 47% of lysophosphatidylcholine produced by phospholipid hydrolysis without recovering [3H]spiperone binding activity. However, the presence of 2.5% albumin during phospholipase A2 action (1.5 micrograms/mg protein) prevents the inhibitory effect of phospholipase on [3H]spiperone binding to the membranes, although 28% of the total membrane phospholipid is hydrolysed. Lysophosphatidylcholine, a product of phospholipid hydrolysis, mimics the phospholipase A2 effect on receptor activity, but the [3H]spiperone binding inhibition can be reversed by washing with 2.5% defatted serum albumin. Addition of microsomal lipids to microsomal membranes pretreated with phospholipase does not restore [3H]spiperone stereospecific binding. It is concluded that the phospholipase-mediated inhibition of [3H]spiperone binding activity results not only from hydrolysis of membrane phospholipids, but also from an alteration of the lipid environment by the end products of phospholipid hydrolysis.
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PMID:Effect of phospholipase digestion and lysophosphatidylcholine on dopamine receptor binding. 673 61

Bilirubin diglucuronide and bilirubin monoglucuronide are formed on incubation of microsomal preparations from rat liver with bilirubin and UDPglucuronate. Microsomal diglucuronide formation is a two-step reaction: first monoglucuronide is formed and this is subsequently converted to diglucuronide. Both steps require UDPglucuronate and have a similar pH optimum at pH 7.8. Albumin inhibits the conversion of monoto diglucuronide. Factors favouring diglucuronide formation are: (a) low bilirubin concentration; (b) relatively high UDPglucuronate concentration; (c) complete removal of UDPglucuronyltransferase latency. For the latter, trypsin-treatment appeared superior over digitonin or UDP-N-acetylglucosamine. Trypsin-treatment had to be done under strictly anaerobic conditions. If trypsin treatment was done under aerobic conditions, reactive molecules were formed which initiated the rapid oxidation of bilirubin and its glucuronides. Microsomal oxidation of bilirubin and glucuronides also occurred in untreated and digitonin-treated microsomes and was stimulated by NADPH and by the cytochrome P-450 inhibitor, metyrapone. This suggests that lipid peroxides act as initiators of bilirubin oxidation. Indirect evidence was found that trypsin inactivates nucleotide pyrophosphatase. This is an active UDPglucuronate-consuming enzyme in microsomal preparations which must be inactivated before meaningful kinetic studies can be done. With trypsin-treated microsomal preparations the Vmax for bilirubin monoglucuronide formation was 1.7 X 10(-9) mol . mg protein-1 . min-1 and KUDPglucuronatem 43 X 10(-6) M. For bilirubin diglucoronide formation the apparent Vmax was 0.7 X 10(-9) mol . mg protein-1 . min-1 and the apparent KUDPglucuronate m 1.0 X 10(-3) M.
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PMID:Microsomal conjugation and oxidation of bilirubin. 687 Dec 45


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