Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two fragments were isolated from BSA one was derived from the first terminal third of the molecule and the second from the last third of the molecule. Each fragment inhibited the reaction of BSA-anti BSA by 90% or better. An immunoabsorbent of each bound 90% of anti BSA. Each fragment bound two antibody molecules per mole of fragment. These results are explained by the concept that BSA contains repeating identical or similar antigenic determinants. Conformational non identity of various batches of BSA was revealed by reactivity of the disulfide bonds at the neutral transition. Trypsin was found to cleave GSA, PSA, and HSA to yield an immunochemically reactive fragment. At least in the case of HSA, the fragment exhibited all the immunochemical reactivity of the native protein.
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PMID:Immunochemistry of bovine serum albumin. 8 78

NADH-cytochrome b5 reductase [EC 1.6.2.2] has been solubilized with Triton X-100 and purified to homogeneity from rabbit liver microsomes. The purified enzyme is essentially free of the detergent and phospholipids and exists in aqueous media as an oligomeric aggregate of about 13 S. Its monomeric molecular weight is about 33,000 and 1 mole of FAD is associated with 1 mole of the monomeric unit. The enzyme catalyzes the reductions by NADH of ferricyanide and 2,6-dichlorophenol indophenol at an activity ratio of 1 : 0.09. Although the intact form of cytochrome b5 is a poorer electron acceptor than its hydrophilic fragment for the purified flavoprotein, electron transfer from the reductase to the intact cytochrome can be markedly stimulated by detergents or phospholipids, which also cause profound enhancement of the NADH-cytochrome c reductase activity reconstituted from the reducatse and cytochrome b5. Upon digestion with trypsin [EC 3.4.21.4], the ability of the reductase to form an active NADH-cytochrome c reductase system with the intact form of cytochrome b5 and Triton X-100 is rapidly lost. This loss of the reconstitution capability can be prevented by preincubation of the reductase with phosphatidylcholine liposomes. Trypsin digestion also results in the cleavage of the reductase molecule to a protein having a molecular weight of about 25,000 and a smaller fragment. The purified flavoprotein can bind to liver microsomes, liver mitochondria, sonicated human erythrocyte ghosts, and phosphatidylcholine liposomes. The reductase solubilized directly from liver microsomes by lysosomal digestion however, is devoid of membrane-binding capacity. It is concluded that the intact form of NADH-cytochrome b5 reductase is an amphipathic protein and its hydrophobic moiety, which is removable by lysosomal digestion, is responsible for the tight binding of the reductase to microsomes and for its normal functioning in the membrane.
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PMID:Purification and properties of the intact form of NADH-cytochrome b5 reductase from rabbit liver microsomes. 17 49

Two species of T-kininogen which release T-kinin (Ile-Ser-bradykinin) have been purified from plasma of rats treated with Freund's complete adjuvant. The molecular weight was estimated to be 69,000 for either T-kininogen I and II by SDS-polyacrylamide gel electrophoresis. Trypsin released one mole of T-kinin from one mole of either T-kininogen, but glandular kallikrein, including rat urinary and rat submandibular gland kallikreins and human urinary kallikrein, did not release any kinin from T-kininogens. Cathepsin D, which was purified from rat liver, released T-kinin from T-kininogens at pH 4.0. These results indicate that rat plasma contains two types of T-kininogen which differ from high molecular weight and low molecular weight kininogens.
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PMID:Isolation and properties of two rat plasma T-kininogens. 354 20

In this study, we purified insulin-like substance (ILS) in the human pancreatic juice by the combined use of affinity chromatography and radioimmunoassay (RIA). The amino acid sequence of ILS in the N-terminal region is the same as that of human insulin. The influence of the enzymes present in the pancreatic juice on the RIA procedure, was examined. Trypsin, chymotrypsin and amylase showed steep influences on radioactivity. The addition of enzyme inhibitors could not reduce pseudo-activity, but the elimination of enzymes in the pancreatic juice by ultrafiltration with the Mole-Cut (Millipore, Japan) resulted in a lowering of the pseudo-insulin activity. Affinity chromatography on Sepharose 4B coupled with anti-porcine insulin was used to capture ILS. ILS was eluted by 1 M acetic acid from the affinity column monitoring pH and the insulin activity by RIA. The amino acid sequences of two components of ILS in amino terminal region were Phe-Val and Gly-Ile-Val. This indicates that ILS obtained from human pancreatic juice was the insulin derived from endocrine secretion of pancreas.
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PMID:Identification of insulin in the human pancreatic juice. 354 48

The effects of incubation of erythrocyte ghosts under various conditions (ionic strength or addition of ankyrin, diamines, or ATP) on the lateral motion of band 3 in the membranes were studied by using the fluorescence photobleaching recovery technique. Incubation of ghosts with exogenous ankyrin increased the immobile fraction of band 3, from 0.6 in intact ghosts to 0.8-0.9 when an average of 0.2 mol of extra ankyrin was bound per mole of band 3. Ankyrin-free band 3 proteins were mobile, but their mobility was governed by the spectrin association state in the cytoskeletal network. The diffusion constant was 5.3 X 10(-11) cm2 s-1 at a spectrin tetramer mole fraction of 0.3-0.4 in 10 mM NaCl/5 mM sodium phosphate, pH 7.8, and decreased 1 order of magnitude when the tetramer fraction increased to 0.5 in higher NaCl concentration (150 mM NaCl). A similar decrease was observed when the spectrin tetramer fraction was increased by 0.2 mM spermine in 10 mM NaCl/10 mM tris(hydroxymethyl)aminomethane hydrochloride, pH 7.6. On the other hand, the rotational motion of band 3 in the membranes was not affected by the spectrin association state. Trypsin treatment of ghosts cleaved off the cytoplasmic domain of band 3 and caused a marked (8-fold) increase in the lateral mobility, D = 4.0 X 10(-10) cm2 s-1. These results indicate that the lateral mobility of ankyrin-free band 3 protein is restricted by interactions of their cytoplasmic domain with the cytoskeletal network. A model is presented that band 3 can pass the network when spectrins are in dissociated dimers and cannot pass when they are tetramers. The lateral diffusion constant is thus determined by the spectrin dimer population in the network.
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PMID:Restriction of the lateral motion of band 3 in the erythrocyte membrane by the cytoskeletal network: dependence on spectrin association state. 379 May 10

We have used both proteolysis and reconstitution experiments to characterize the determinants for LDL receptor binding of HTG-VLDL. In these studies, we showed that the removal of approximately one mole of apo E per mole of HTG-VLDL (Sf 100-400) and HTG-VLDL (Sf 60-100) by thrombin-specific cleavage results in loss of receptor binding and concomitant loss of suppression of HMG-CoA reductase. This is in direct contrast to the lack of effect thrombin cleavage has on the receptor-mediated uptake of LDL, an apo B-mediated process. We were able to reconstitute receptor binding in thrombin-treated HTG-VLDL (Sf 100-400) by the specific reincorporation of one mole of apo E into the VLDL. The incorporation of one mole of apo E into normal non-suppressive VLDL (Sf 60-400) also enables this lipoprotein to bind to the receptor as effectively as LDL. Trypsin, which destroys apo E-mediated, but not apo B-mediated binding to the LDL receptor, abolishes binding of HTG-VLDL (Sf 100-400) and HTG-VLDL (Sf 60-100), but not that of HTG-VLDL (Sf 20-60), IDL, or LDL to the LDL receptor. Therefore, we conclude that apo E of the appropriate conformation is required for receptor-mediated uptake by the LDL receptor of large TG-rich lipoproteins (Sf greater than 60). This conformation of apo E is probably related to the surface on which it is found (i.e., size of the particle) and the mode of incorporation into the phospholipid surface (i.e., transferred from plasma HDL). In large TG-rich particles, it appears that the intact apo E is necessary for the proper orientation of the molecule on the surface, with the carboxy-terminal one-third needed to anchor the apoprotein to the phospholipid surface. We believe that the binding of apo E to the LDL receptor is a redundant system and is used as a backup system in abnormal pathological states such as hypertriglyceridemia, abetalipoproteinemia, and hypobetalipoproteinemia. In the case of hypertriglyceridemia, where the lipolysis mechanism is overloaded, the abnormal binding of HTG-VLDL (Sf greater than 60) provides an alternate catabolic route for their removal from plasma. In the cases of a beta- and hypobetalipoproteinemia, where the normal particles for cholesterol delivery are either absent or at low levels, apo E-containing particles can serve to deliver cholesterol to cells as has been recently observed in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Expression of LDL receptor binding determinants in very low density lipoproteins. 390 64

1. Treatment of low K goat red cells with trypsin stimulated the Na-K pump more than twofold. Dose dependence and time course experiments indicated a half-maximal stimulation at 1.6 mg trypsin/ml. (37 degrees C, 3 hr), and a maximum effect after 5 hr (10 mg/ml). 2. Trypsin had only a small and variable effect on the ouabain-insensitive component of K influx. 3. The Na-K pump activity of high K goat red cells was not affected by trypsinization. 4. When intracellular K was varied by the PCMBS technique, it was found that the trypsin stimulation was greatest (2-5-fold) in cells with the highest K (40 m-mole/1. cells) and lowest (1.1-fold) in cells with low K (<1 m-mole/1. cells). 5. The trypsin effect was reversed by nystatin treatment or hypotonic lysis. 6. Trypsin did not increase the number of ouabain-binding sites. 7. It is concluded that trypsinization modifies the L antigen in low K goat red cells to decrease the apparent internal affinity for K of the Na-K pump in these cells.
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PMID:Stimulation of the sodium-potassium pump by trypsin in low potassium type erythrocytes of goats. 741 31

Bovine pancreatic trypsin was modified by the mono-6-amino-6-deoxy derivatives of alpha-, beta-, and gamma-cyclodextrin through a transglutaminase-catalyzed reaction. The trypsin-cyclodextrin conjugates, containing about 3 mol of oligosaccharide per mole of protein, were tested for their catalytic and stability properties. The specific esterolytic activity and the kinetics constants of trypsin were significantly improved following the transglutaminase-induced structural modifications. Trypsin-cyclodextrin conjugates were also found markedly (sixfold) more resistant to autolytic degradation at alkaline pH, and their thermal stability profile was improved by about 16 degrees C. Moreover, they were particularly resistant to heat inactivation when treated at different temperatures ranging from 45 degrees C to 70 degrees C for different periods of time.
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PMID:Transglutaminase-catalyzed synthesis of trypsin-cyclodextrin conjugates: kinetics and stability properties. 1252 88

A plasmalemma-bound NADH oxidation system (Lin 1982 Proc Natl Acad Sci USA 79: 3773-3776) in corn root protoplasts was isolated by a mild treatment of intact protoplasts with trypsin. The majority of NADH stimulated O(2) consumption activity of the protoplasts could be recovered in the supernatant isolated from the intact protoplasts which have been treated with trypsin. The activation energy of NADH oxidation in the supernatant is similar to that of the intact protoplasts (8.7 versus 9.4 kilocalories per mole per degree). Unlike that of the intact protoplasts, an Arrhenius plot of the temperature response (from 5 to 25 degrees C) of the activity in the supernatant shows no transition suggestive of a dissociation of the enzyme from the membrane. Trypsin treatment did not affect K(+) uptake into cell volume of the protoplast. However, the NADH-stimulated K(+) uptake and the increase of cell volume were greatly reduced. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of trichloroacetic acid-precipitated protein from the supernatant showed one extra peptide band with approximately 42 kilodalton molecular weight.
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PMID:Isolation of NADH Oxidation System from the Plasmalemma of Corn Root Protoplasts. 1666 74