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The interaction of α-1-antitrypsin with chymotrypsin, trypsin and elastase

BBA - Enzymology 1975年第1期391卷 193-200页

作者： Cohen, Allen B. United States

The mode of inhibition of α-1-antitrypsin of chymotrypsin, trypsin and pancreatic elastase was examined by a kinetic method. All three enzymes were completely bound to α-1-antitrypsin;therefore, the dissociation constant of the enzyme-inhibitor complex was too low to measure with these methods. The dissociation constants for the three enzyme-inhibitor complexes were estimated to be < 5 · 10^-9 M. However, α-1-antitrypsin could be specifically displaced from Sepharose-bound elastase with an irreversible inhibitor of that enzyme. Additional experiments showed that dioxane, 20% (v/v), blocked 100% of the inhibition of elastase, 16% of the inhibition of trypsin, and 0% of the inhibition of chymotrypsin. The effect was reversed by diluting the dioxane to 1% (v/v). These findings indicated that α-1-antitrypsin was tightly bound to the three enzymes studied but did not allow discrimination as to the nature of the inhibition. However, the competitive mode of inhibition was suggested by the displacement of α-1-antitrypsin from elastase by an irreversible inhibitor of the enzyme that bound covalently at the enzyme-active site. The variable susceptibility of the enzyme to blockage of the inhibition by low concentrations of p-dioxane suggested that hydrophobic bonds may be important in the interaction with α-1-antitrypsin. © 1975.

关键词： PhMeSo 2 f phenylmethane sulfonyl fluoride

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HYPERCALCEMIA AND TUMOR-PROSTAGLANDINS - VX2 CARCINOMA MODEL IN RABBIT

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METABOLISM-CLINICAL AND EXPERIMENTAL 1975年第8期24卷 973-986页

作者： VOELKEL, Ef TASHJIAN, AH fRANKLIN, R WASSERMAN, E LEVINE, L HARVARD UNIV SCH DENT MED LAB PHARMACOL 188 LONGWOOD AVE BOSTON MA 02115 USA BRANDEIS UNIV GRAD DEPT BIOCHEM WALTHAM MA USA HARVARD UNIV MED SCH DEPT PHARMACOL BOSTON MA 02115 USA

The VX2 carcinoma produces profound hypercalcemia (17–22 mg 100 ml ) in the rabbit about 3–4 wk after transplantation. A bone resorption-stimulating factor (assayed in vitro with mouse calvaria in culture) has been extracted with diethyl ether from the tumor tissue and from the medium of a clonal strain of VX2 cells grown in culture. Serologic methods reveal that the tumors contain 294 ± 51 ng/g fresh weight (mean ± SE, 25 tumors) of prostaglandin E2 (PGE2 ), a potent bone resorption-stimulating agent. VX2 cells in culture produce 0.5–3.0 μg PGE2 per mg cell protein per 24 hr. The production of bone resorption-stimulating activity and PGE2 by VX2 cells in culture were both inhibited by indomethacin (100 ng/ml). Tumors from normocalcemic, indomethacin-treated rabbits (10–40/mg rabbit 24 hr) contained little or no bone resorption-stimulating activity nor PGE2 . Tumor-bearing rabbits receiving indomethacin continuously did not develop hypercalcemia; however, following cessation of indomethacin administration, hypercalcemia developed rapidly and was again reversed by reinstitution of indomethacin feeding. In untreated, hypercalcemic, tumor-bearing rabbits, initiation of indomethacin treatment was followed by a rapid return of the plasma calcium to the normal range. Systemic venous plasma from hypercalcemic tumor-bearing rabbits contained higher concentrations of PGE2 than plasma from normocalcemic control rabbits. Venous drainage of the tumor contained even higher plasma PGE2 concentrations than systemic venous plasma in hypercalcemic animals; plasma PGE2 concentrations locally and in systemic plasma were unmeasurable (<70 pg/ml) in normocalcemic, indomethacin-treated, tumor-bearing rabbits. We conclude that PGE2 is a bone resorption-stimulating factor produced by VX2 tumor cells, and that secretion of PGE2 by the tumor in vivo may well be responsible for the hypercalcemia observed in tomor-bearing rabbits.

关键词： PGE PGA PGf and PGB for prostaglandins of the E A f and B series respectively

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MUTATIONS IN PROTEINS AND BASE CHANGES IN CODONS

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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS 1975年第1期66卷 1-8页

作者： JUKES, TH UNIV CALIF SPACE SCI LABBERKELEYCA 94720

About 300 single-amino-acid mutations in proteins were compared with the corresponding changes in the amino acid code. Transitional base changes are more common than transversions. Among transitions AG interchanges are more common than CU interchanges and AU interchanges are the most infrequent of transversions. Of the 17 undiscovered single-amino-acid mutations, 15 are transversions that do not produce a change in charge.

关键词： Y Y R R N N N N f L I M V S P T A Y CT H Q N K D E C W R G

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TRACE-ELEMENTS - SELECTIVE SURVEY

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CLINICAL CHEMISTRY 1975年第4期21卷 476-500页

作者： REINHOLD, JG PAHLAVI UNIV COLL MED DEPT BIOCHEM SHIRAZ IRAN NEMAZEE HOSP INST NUCL MED MED RES UNIT SHIRAZ IRAN

trace elements, history, tissue content, metabolic functions, sources and absorption, clinical disorders and other effects of deficiencies, and other reviews on I, fe, Zn, Cu, Cr, Co, Mn, Mo, V, Ni, Se, Si, Sn, f

关键词： trace elements history tissue content metabolic functions sources and absorption clinical disorders and other effects of deficiencies and other reviews on I fe Zn Cu Cr Co Mn Mo V Ni Se Si Sn f

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BROWN ADIPOSE-TISSUE MITOCHONDRIA

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BIOCHIMICA ET BIOPHYSICA ACTA 1975年第1期416卷 53-103页

作者： fLATMARK, T PEDERSEN, JI UNIV BERGEN DEPT BIOCHEM ARSTADVOLLEN BERGEN NORWAY UNIV OSLO INST NUTR RES BLINDERN NORWAY

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EffECTS Of QUERCETIN AND f1 INHIBITOR ON MITOCHONDRIAL ATPASE AND ENERGY-LINKED REACTIONS IN SUBMITOCHONDRIAL PARTICLES

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BIOCHIMICA ET BIOPHYSICA ACTA 1974年第2期333卷 180-186页

作者： LANG, DR RACKER, E CORNELL UNIV SECT BIOCHEM MOLECUL & CELL BIOLITHACANY 14850

Quercetin (3,3′,4′,5,7-pentahydroxyflavone) shares certain properties with the mitochondrial ATPase inhibitor protein. At low concentrations it inhibits both soluble and particulate mitochondrial ATPase and has no effect on oxidative phosphorylation in submitochondrial particles. Unlike the mitochondrial inhibitor protein quercetin inhibits the ATP-dependent reduction of NAD + by succinate in fully reconstituted submitochondrial particles. A comparison of various flavones indicates that the hydroxyl groups at the 3′ and perhaps 3 position are important for the inhibition of ATPase activity.

关键词： f 1 coupling factor 1 (ATPase) A particles (EDTA particles) submitochondrial particles prepared by sonication of beef heart mitochondria in the presence of ammonia and EDTA

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The equilibrium between the mitochondrial ATPase (f₁) and its natural inhibitor in submitochondrial particles

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BBA - Bioenergetics 1974年第2期347卷 240-252页

作者： Van de Stadt, R.J. Van Dam, K. Laboratory of Biochemistry B.C.P. Jansen Institute University of Amsterdam Plantage Muidergracht 12 AmsterdamThe Netherlands

1. The reversible equilibrium between the mitochondrial ATPase (f1) and its naturally occurring inhibitor in Mg-ATP submitochondrial particles has been studied under different conditions. 2. High ionic strength favour... 详细信息

1. The reversible equilibrium between the mitochondrial ATPase (f₁) and its naturally occurring inhibitor in Mg-ATP submitochondrial particles has been studied under different conditions. 2. High ionic strength favours dissociation of the ATPase inhibitor as tested by ATPase and ATP-driven transhydrogenase activities. 3. Dissociation of the ATPase inhibitor results in an increased maximal velocity of the ATPase activity measured in the presence of uncoupler and an increased affinity for adenine nucleotides, in particular for ATP. 4. Association of the ATPase inhibitor with inhibitor-depleted Mg-ATP particles causes a slowing of the initial rate of succinate oxidation. 5. The antibiotic aurovertin stimulates the ATPase activity of Mg-ATP particles preinculbated in the presence of a supply of oxidative energy. Bound aurovertin impedes the association of inhibitor-deficient particles with ATPase inhibitor. 6. The fluorescence of aurovertin bound to inhibitor-containing particles is much less than that of aurovertin bound to inhibitor-depleted particles. 7. The oligomycin-sensitivity-conferring protein, added either alone or in the presence or absence of membranous components of the ATPase complex, has little or no effect on the fluorescence of the f₁-aurovertin complex. 8. It is suggested that the ATPase inhibitor brings f₁ in a conformation denoted *f₁ that binds aurovertin with a low quantum yield, a decreased affinity and an increased binding capacity. © 1974.

关键词： f 1 mitochondrial ATPase OSCP oligomycin-sensitivity-conferring protein I mitochondrial ATPase inhibitor A particles submitochondrial particles prepared by sonication of beef-heart mitochondria in an alkaline solution at pH 9.2 AS particles submitochondrial particles prepared by treatment of A particles with Sephadex G-50 Mg-ATP particles submitochondrial particles prepared by sonication of beef-heart mitochondria in the presence of 15 mM MgCl 2 and 1 mM ATP (pH 7.5) TES N -tris(hydroxymethyl)methyl-2-aminoethanesulphonic acid fCCP carbonyl cyanide p -trifluoromethoxyphenylhydrazone 1799 α,α′-bis(hexafluoroacetonyl)acetone

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AMINO-ACID SEQUENCE Of SHEEP CARBONIC-ANHYDRASE C

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BIOCHIMICA ET BIOPHYSICA ACTA 1974年第2期371卷 534-548页

作者： TANIS, RJ fERRELL, RE TASHIAN, RE UNIV MICHIGAN MED SCHDEPT HUMAN GENETANN ARBORMI 48104

The sequence of amino acid residues comprising the major form of sheep red cell carbonic anhydrase C has been determined. The primary sequences of peptides derived from cyanogen bromide cleavage and tryptic digestion were obtained primarily through the use of the Edman degradation procedure. The ordering of these peptides in the sheep molecule is based on the high degree of homology between the sheep enzyme and the previously sequenced human and bovine carbonic anhydrase C molecules. Based on comparisons with the three-dimensional structure of human carbonic anhydrase C, the function of certain residues which appear to be involved either in the maintenance of structure or in the active site of the sheep enzyme is discussed.

关键词： f 3 Ac trifluoroacetic acid MalNEt N- ethylmorpholine

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PARTIAL-PURIfICATION AND PROPERTIES Of OVINE LIVER HYDATID CYST fLUID AND HEALTHY OVINE LIVER PHOSPHOGLUCOSE ISOMERASES

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CLINICA CHIMICA ACTA 1974年第3期53卷 299-304页

作者： fARADJI, B VESSAL, M GHALAMBO.MA PAHLAVI UNIV DEPT BIOCHEMSHIRAZIRAN

Echinococcosis is a disease prevalent both in man and animals with no effective therapeutic measures established against it so far, except for surgical removal of the cyst in humans. Attempts have been made to compare the properties of certain enzymes present in the parasite with those of the corresponding host in the hope of discovering inhibitors that would inhibit the parasite enzyme(s) selectively. In the present report certain properties of phosphoglucose isomerase of the ovine liver cyst fluid have been compared with those of the healthy ovine liver. The enzymes from both sources purified by the same procedure exhibited the following properties: (1) identical pH optimum (8.5), (2) no detectable inhibition in the presence of phosphate ion up to 4.1 mM, (3) marked differences in the K_m value, 8.7 mM and 10.7 mM for the parasite and host enzymes respectively, and (4) higher thermostability of the parasite enzyme as compared with the host enzyme.

关键词： PGI phosphoglucose isomerase G-6-P α-D-glucose 6-phosphate f-6-P α-D-fructose 6-phosphate f D-fructose EDTA ethylnediaminetetra-acetate (sodium salt) DEAE diethylaminoethyl

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BINDING Of AUROVERTIN TO PHOSPHORYLATING SUBMITOCHONDRIAL PARTICLES

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BIOCHIMICA ET BIOPHYSICA ACTA 1974年第2期347卷 253-263页

作者： VANDESTADT, RJ VANDAM, K UNIV AMSTERDAM BCP JANSEN INST LAB BIOCHEM PLANTAGE MUIDERGRACHT 12 AMSTERDAM NETHERLANDS

1. The slow enhancement of the fluorescence of the complex between aurovertin and Mg-ATP particles, induced by succinate oxidation in the absence of adenine nucleotides and phosphate, is completely accounted for by dissociation of the natural ATPase inhibitor from the particles. 2. The large increase in the aurovertin fluorescence induced by an anaerobicaerobic transition requires the presence of all State-3 components (substrate, ADP, phosphate and Mg 2+ ). This change is very rapid with a half-time of 20 ms. 3. There are two aurovertin-binding sites on Mg-ATP particles, one with high affinity and one with low affinity. Binding of aurovertin to the strong sites is positively cooperative only under State-3 conditions. 4. The quenching of the fluorescence of the particle-aurovertin complex induced by an uncoupler is rapid and extensive in the presence of ATP. The rapid quenching induced by an uncoupler is followed by a slow increase in the aurovertin fluorescence, that may be attributed to a redistribution of bound adenine nucleotides. All uncoupler-induced changes are prevented by oligomycin. 5. Excess oligomycin added to Mg-ATP particles oxidizing succinate under State-3 conditions initially induces a rapid enhancement of the aurovertin fluorescence. The pH dependency of this change suggests that this rise may be attributed to the induction of a maximally ‘coupled’ membrane.

关键词： f 1 mitochondrial ATPase Mg-ATP particles phosphorylating submitochondrial particles prepared by sonication of beef-heart mitochondria in the presence of 15 mM MgCl 2 and 1 mM ATP (pH 7.5) fCCP carbonyl cyanide p -trifluoromethoxyphenylhydrazone 1799 α,α′-bis(hexafluoroacetonyl)acetone TTfB 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole

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