Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:APRD00631 (Gel)
 14,881 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An alkaline aminopeptidase was isolated from the culture medium of Penicillium roqueforti. The enzyme was purified by ammonium sulfate precipitation, filtration on Bio-Gel P-100, chromatography on D.E.A.E.-cellulose and hydroxylapatite, filtration on Bio-Gel P-150 and electrofusing. The purified preparation was homogeneous on polyacrylamide gel electrophoresis at pH 8.5. The molecular weight of the enzyme was estimated to be about 35,000 daltons. The isoelectric point is 4.5. The optimum pH for L-leucine-p-nitroanilide hydrolysis is 8.0. At 35 degrees C the enzyme is stable between pH 6.0 and 7.0. Ethylenediamine tetraacetic acid and a sulfhydryl reagent (p-hydroxymercuribenzoate) inhibit the activity, but the enzyme is insensitive to diisopropylfluorophosphate. Hydrolysis of synthetic peptides shows that the enzyme releases apolar amino acids. Dipeptides are poorly hydrolyzed and Gly in penultimate or N-terminal position causes poor activity. The enzyme is able to cleave the N-terminal Arg-Pro bond of bradykinin.
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PMID:The proteolytic system of Penicillium roqueforti. V. -- Purification and properties of an alkaline aminopeptidase. 2 80

Proteases capable of activating procollagenase from gingiva and from fibroblast and macrophage monolayer cultures were harvested from homogenates of canine tumor mast cells. The mast cell proteases lysed casein and Azocoll but not native collagen. In low salt concentrations the enzymes existed at high molecular weight complexes, which were dissociated by increasing the salt concentration above 1.0 M (NaCl, KCl). Gel filtration in 1.4 M KCl separated the protease activity into three peaks, all of which activated procollagenase. Two of the enzymes showed substrate specificities (hydrolysis of p-tosyl-L-arginine methyl ester and benzoyl-tyrosine ethyl ester) and reactive center reactivities similar to pancreatic trypsin and chymotrypsin. Based on gel filtration, apparent molecular weights of 160 000 (p-tosyl-L-arginine methyl ester esterase), 90 000 (main procollagenase activator) and 36 000 benzoyl-tyrosine ethyl ester esterase) were determined. Activation of procollagenase resulted in a 18-20 000 decrease of the molecular weight. The activation was directly related to the amount of activator added within certain limits. Further addition of activator resulted in proteolytic inactivation of collagenase.
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PMID:Activation of fibroblast procollagenase by mast cell proteases. 5 9

Basal immunoreactive glucagon was elevated in four of nine asymptomatic relatives of a patient with glucagonoma. Immunoreactive glucagon remained elevated throughout 22 to 25 hours of continuous observation. Glucagon responses to intravenous glucose and arginine or mixed meals (or both) were abnormal, whereas glucose and insulin responses were normal. Gel filtration of plasma revealed that over 85 per cent of the four relatives' immunoreactive glucagon had a molecular weight of greater than 9000 daltons whereas that of 70 per cent of the patients with glucagonoma had a molecular weight of 3500 daltons, with the remainder eluting in the area of 9000 daltons. Pancreatic angiograms and hepatic scintiscans were normal in all four relatives. The data suggest an autosomal dominant transmission of hyperglucagonemia in this family. Immunoreactive glucagon with a molecular weight of 3500 or 9000 daltons appears to be required for the development of the clinical glucagonoma syndrome.
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PMID:Familial hyperglucagonemia--an autosomal dominant disorder. 18 88

The exposure of apolipoproteins at the surface of human plasma high density lipoproteins (HDL) was assessed by their accessibility to agarose-immobilized forms of trypsin and chymotrypsin. Proteolysis of lipid-free apolipoproteins and the lipoprotein subfractions HDL2 (d = 1.08--1.125 g/ml) and HDL3 (d = 1.125--1.195 g/ml) that differ in lipid-to-protein ratio was compared by polyacrylamide gel electrophoresis and isoelectric focusing of the apolipoproteins and peptide fragments and by quantitation of the various carboxyl-terminal groups formed. Gel filtration of the proteolyzed lipoproteins on Sephadex G-150 column indicated that more than 90% of the apolipoproteins and peptides remain associated with lipoprotein complexes. Proteolysis of lipoproteins occurred more slowly and with less fragmentation of the lipoproteins and apolipoproteins than proteolysis of thelipid-free apolipoproteins or the proteolysis of lipoproteins by soluble proteases reported by other investigators. The difference in lipid content of HDL2 and HDL3 made little difference in their proteolysis. Proteolysis of the lipoproteins by agarose-trypsin was more rapid at 37 degrees C than at 22 degrees C, but the proteolytic products were similar and differed from the products from the lipid free proteins. Peptide fragments from lipoproteins were larger than those from lipid-free proteins, which suggests masking of potentially cleavable groups by lipid. The amounts (mol/g protein) of new carboxyl-terminal tyrosine and phenylalanine released by agarose -chymotrypsin were much greater from the lipid-free proteins, but about 3/4 of the tryptophan residues were inacessible in both lipoproteins and lipid-free proteins. In agarose-trypsin digestion, lysine residues were slightly more masked than arginine in the absence of lipids and much more so in the lipoproteins. However, in the lipoproteins apoA-II, which contains lysine but no arginine, was cleaved more rapidly and extensively by agarose-trypsin than apoA-I.
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PMID:Surface exposure of apolipoproteins in high density lipoproteins. I. Reactivities with agarose-immobilized proteases. 20 44

A case of glucagonoma syndrome with necrolytic migratory erythema, glossitis, anemia, hyperglucagonemia and a malignant, pancreatic A-cell tumour in a 68-year-old male is described. Gel filtration of the highly elevated circulating glucagon immunoreactivity (2200 pg/ml) demonstrated 60% pancreatic glucagon and 30% "proglucagon". Metabolic studies before operation demonstrated suppression of the total plasma glucagon concentration on oral glucose tolerance test, unchanged total plasma glucagon concentration during intravenous glucose tolerance test and insulin-induced hypoglycemia. Administration of arginine was followed by a rise in both the pancreatic glucagon and the "proglucagon", whereas alanine increased only the pancreatic glucagon. The plasma somatostatin level was immeasurable preoperatively. Somatostatin infusion completely suppressed the release of the pancreatic glucagon but did not significantly affect the "proglucagon". After removal of the tumour the skin lesions disappeared and the total plasma glucagon values fell to normal levels (120 pg/ml). Also, other abnormal laboratory findings returned to normal, including the preoperatively observed renal glucosuria.
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PMID:Metabolic studies and glucagon gel filtration pattern before and after surgery in a case of glucagonoma syndrome. 21 26

High density lipoproteins (HDL) in the plasma from cholestatic rats were studied by gel filtration, polyacrylamide gel electrophoresis and electron microscopy. HDL from cholestatic rats separated into two subfractions, abnormally enlarged particles and smaller ones, on gel filtration through Bio-Gel A 1.5 m. Polyacrylamide gel electrophoresis in 8 M urea revealed that the relative proportion of C-III-3 peptide in C-apoproteins was higher in the two HDL subfractions from cholestatic rats than in normal HDL. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed that the abnormally enlarged HDL contained the 'arginine-rich' apoprotein, whereas a band corresponding to 'arginine-rich' apoprotein was only faintly visible in the smaller HDL subfraction. Normal HDL contained much smaller amount 'arginine-rich' apoprotein than the enlarged HDL. In electron microscopy, both of the two subfractions of cholestatic HDL appeared spherical. The abnormally enlarged HDL were consisted of particles with a diameter of 17 +/- 4.5 nm (mean +/- S.D.). The other subfraction contained smaller particles with a diameter (about 10 nm) similar to normal HDL.
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PMID:Alterations of high density lipoproteins in experimental cholestasis in the rat. 22 39

The extracellular protease of Pseudomonas maltophilia was partially purified by ammonium sulfate precipitation and chromatography on Sephadex G-75 and Bio-rex 70. Gel electrophoresis revealed minor impurities. The enzyme exhibited the following properties: (i) molecular weight, 35,000; (ii) A see article; 10.8; (iii) isoelectric point, 9.3; (iv) pH optimum, 10.0; (v)s20, w equal 3.47. The enzyme was rapidly inactivated by ethylenediaminetetracetate, but activity could be partially restored with divalent cations. Of those tested, Ca2+, Sr2+, Ba2+, Co2+, Cu2+, Mg2+, and Zn2+ were all effective. Both phenylmethylsulfonylfluoride and diisopropylfluorophosphate were powerful inhibitors of protease activity, but L-1-tosylamide-2-phenylethylchloromethyl ketone, iodoacetic acid, and iodoacetamide were without effect. The enzyme hydrolyzed the esters N-acetyl-L-tyrosine ethyl ester and alpha-N-benzoyl-L-arginine ethyl ester (BAEE) with Km values of 10.4 and 3.4 mM, respectively. The hydrolysis of BAEE was also inhibited by phenylarsonic acids. The kinetics of inhibition by m-nitrophenylarsonate were of the mixed type, and the K1 was 1.8 mM. The data followed a theoretical curve for a 1:1 enzyme-inhibitor complex with a dissociation constant of 1.8 mM. Inhibition by m-nitrophenylarsonate was pH dependent and followed a theoretical curve for the titration of a protonated group with a pKa of 7.0.
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PMID:Purification and properties of a serine protease from Pseudomonas matophilia. 23 50

Arginase has been isolated from granulocytes of a patient with chronic myelocytic leukemia and from lymphocytes of a patient with chronic lymphocytic leukemia and both enzymes have been purified to apparent homogeneity. The purification procedure employed acetone extraction, ammonium sulfate precipitation, DEAE-cellulose and CM-Sephadex chromatography and gel filtration on Bio-Gel A 1.5m. Both enzymes appear to be metalloenzymes, and to have molecular weights of about 120 000. Studies with the dissociated enzymes suggest that the subunit molecular weight is about 37 000, in agreement with a tetrameric aggregate structure of the native enzymes. Human leukemic granulocyte and lymphocyte arginases are strongly basic proteins with pI values between 9.25 and 9.35. Their free -SH groups enabled them to be linked to organomercurial-agarose. The kinetic properties estimated for both enzymes showed an optimum pH of 8.5, and an optimal MnCl2 concentration of 0.01 M. The Km for L-arginine is 2.7-3.1 mM and L-ornithine exhibits a mixed type of inhibition, with a Ki of 15.5-15.7 mM.
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PMID:Purification of arginases from human-leukemic lymphocytes and granulocytes: study of their physicochemical and kinetic properties. 24 Jul 2

Egg-laying hormone (ELH), a neuropeptide synthesized by the bag cell neurons, induces egg laying and its correlated behavior in Aplysia californica. In the present study, ELH has been purified to homogeneity and its primary structure has been determined. We find this molecule to have 36 amino acid residues with a M(r) of 4385 and a calculated isoelectric point of 9.7. Direct microsequence analysis revealed a single amino acid sequence that is in agreement with the amino acid composition determined after acid hydrolysis of ELH: H-Ile-Ser-Ile-Asn-Gln-Asp-Leu-Lys-Ala-Ile-Thr-Asp-Met-Leu-Leu-Thr-Glu-Gln- Ile-Arg-Glu-Arg-Gln-Arg-Tyr-Leu-Ala-Asp-Leu-Arg-Gln-Arg-Leu-Leu-Glu-Lys-OH. Enzyme data indicate that the COOH-terminal lysine may be modified but its exact nature remains to be determined. There is no similarity between the amino acid sequence of ELH and that of presently known vertebrate neuropeptides. The two-step purification procedure, starting with a homogenate of bag cell clusters, consisted of cation exchange chromatography on SP C25 (Sephadex) followed by gel filtration on Bio-Gel P-6. Our purification results in a 100-fold enrichment of ELH from bag cell homogenates and a 36% recovery of purified radiolabeled marker ELH. Analysis of purified ELH radiolabeled with [(35)S]methionine or [(3)H]leucine on isoelectric focusing gels and on 8 M urea/sodium dodecyl sulfate gels showed only a single peak containing 90% of the radiolabel. Radiolabeled ELH migrated with a pI of 9.0-9.2 and an apparent M(r) of 3500-5700. ELH retained egg-laying bioactivity when eluted from this segment of the gel. We find that 2.5 nmol of pure ELH consistently induces egg laying at 20 degrees C.
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PMID:Purification and primary structure of the neuropeptide egg-laying hormone of Aplysia californica. 29 51

The amino acid sequences of human histones have been investigated for studies of histone evolution. The whole histone was prepared from human spleen and was separated into 3 fractions, H4+H3+H2A, H2B, and H1, by our technique of CM-cellulose chromatography. The H2B fraction was further purified by Bio-Gel P-60 chromatography. For sequence determination, the H2B molecule was first split into 4 major fragments I to IV, by limited chymotryptic digestion at pH 5.0 and 15 degrees C, followed by Sephadex G-50 chromatography. Fragments I and III were then digested with trypsin, yielding 18 and 16 peptides, respectively, on column and paper chromatographies. Sequence analyses of these tryptic peptides, as well as chymotryptic fragments II and IV, showed no differences from the corresponding parts of calf thymus H2B sequence, making it possible to locate fragments I to IV at residues 1--40, 41--42, 43--121 and 122--125 of the total sequence. The only new findings were microheterogeneities at residues 39 (75% valine and 25% isoleucine) and 124 (70% serine and 30% alanine). The sequence of the most basic cluster at residues 27--24, -Lys-Lys-Arg-Lys-Arg-Ser-Arg-Lys-, was confirmed with a peptide obtained from fragment I by staphylococcal protease digestion. Thus, it is concluded that the H2B sequence of lower mammals was conserved during the evolutionary process leading to man.
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PMID:Human spleen histone H2B. Isolation and amino acid sequence. 42 50


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