解剖学和形态学
麻醉学
听力与言语-语言病理学
行为科学
心脏和心血管系统
细胞和组织工程学
临床神经病学
危重症监护医学
牙科,口腔外科和医学
皮肤病学
急诊医学
内分泌学和新陈代谢
肠胃学和肝脏学
老人病学和老年医学
卫生保健科学和服务
血液学
免疫学
传染病
综合和补充性医学
医学伦理学
医学信息学
医学实验室技术
医学,全科和内科
医学,法律
医学,研究和试验
神经系统科学
护理
营养学和饮食学
产科医学和妇科医学
肿瘤学
眼科学
整形外科学
耳鼻喉科学
病理学
儿科学
周围血管疾病
药理学和药剂学
生理学
基本医疗保健
精神病学
公共、环境和职业卫生
放射学,核医学和医学成像
康复学
生殖生物学
呼吸系统
风湿病学
运动科学
外科学
毒理学
热带医学
泌尿学和肾脏学
病毒学
老年医学
健康政策和服务
心理学,临床
abstract::Kinetic studies of the effect of addition of Co2+ or Mn2+ to a highly purified dipeptidase from Ehrlich-Lettré mouse ascites tumor cells show that these metals specifically activate the hydrolyses of certain classes of dipeptides. This enzyme was previously (S. Hayman and E. K. Patterson, 1971, J. Biol. Chem. 246, 660...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00690a018
更新日期:1975-09-23 00:00:00
abstract::The stoichiometry of the nitrogenase ATP-dependent H2 evolution and ecetylene reduction reactions using S2O4(2-) as an electron source was studied by various techniques. For each mole of S2O4(2-) oxidized to 2SO3(2-) by the enzyme-catalyzed reactions at 25 degrees and pH 8, 1 mol of H2 (1 mol of ethylene for acetylene...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00690a019
更新日期:1975-09-23 00:00:00
abstract::N-Ethylmaleimide modified heavy meromyosin in only 3-fold activated by actin rather than 200-fold as is normal heavy meromyosin (Silverman, R., Eisenberg, E., and Kielley, W. W. (1972), Nature (London) 240, 207). Ultracentrifuge studies demonstrated that in the absence of ATP the N-ethylmaleimide modified heavy merom...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00688a020
更新日期:1975-08-26 00:00:00
abstract::The binding of formate ion, a substrate for the peroxidatic reaction of catalase, has been investigated by magnetic resonance techniques. Comparative studies of formate binding to ferric myoglobin have also been performed. The nuclear magnetic relaxation (NMR) rate of formate and water protons is enhanced by the prese...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00688a023
更新日期:1975-08-26 00:00:00
abstract::Kinetic studies of reactions between fluorescein and antifluorescein antibody produced during early, intermediate, and late stages of the immune response have been carried out utilizing both fluorescence intensity and polarization measurements in the static (time constant similar to 5 sec) and in the stopped-flow mode...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00688a009
更新日期:1975-08-26 00:00:00
abstract::An improved procedure for the preparation of cobalt-cytochrome c has been developed. Various factors influencing the cobalt insertion process are discussed. The optical spectra of cobalt-cytochrome c suggest a six-coordinated species. The spectral shifts occurring with oxidation-reduction are compared with those obser...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00687a003
更新日期:1975-08-12 00:00:00
abstract::Chromatography on a column of SP-Sephadex shows that commercial chymopapain contains three components with proteolytic activity. Each behaves as a single protein upon rechromatography and electrophoresis on polyacrylamide gels. The major component, which represents 31% of the activity applied to the column and is the ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00687a028
更新日期:1975-08-12 00:00:00
abstract::Porcine parathyroid gland slices were incubated with 3H-labeled amino acids in order to label tissue proteins. After incubation a crude hormonal extract was prepared and analyzed by chromatography on carboxymethylcellulose. Among the three radioactive peaks which were detected in the eluate, two were identified as par...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00687a018
更新日期:1975-08-12 00:00:00
abstract::The hydrogen exchange kinetics of the complex of trypsin-soybean trypsin inhibitor (Kunitz) have been compared to the calculated sum of the exchange kinetics for the inhibitor and trypsin measured separately. The exchange rates observed for the complex are substantially less than the sum of the exchange rates in the t...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00686a020
更新日期:1975-07-29 00:00:00
abstract::The homogeneous, single-walled phosphatidylcholine-cholesterol mixed vesicles were prepared by ultrasonic irradiation of egg phosphatidylcholine in the presence of various amounts of cholesterol in solution at 4 degrees under a nitrogen atmosphere followed by molecular sieve chromatography on a Sepharose 4B column. Ph...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00686a012
更新日期:1975-07-29 00:00:00
abstract::Oligoribonucleotide binding to baker's yeast initiator tRNA was measured by equilibrium dialysis in order to determine which regions of the tRNA were free to bind complementary oligomers and which were involved in secondary and tertiary structure. Association constants of trinucleoside diphosphates and tetranucleoside...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00686a004
更新日期:1975-07-29 00:00:00
abstract::Limited digestion of polysomal RNA with pancreatic ribonuclease releases a structure consisting of poly(A) associated with other polyribonucleotide sequences. This complex can be purified by oligo(dT)-cellulose chromatography. Heating for formamide treatment causes the dissociation of fragments free of poly(A) from th...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00686a024
更新日期:1975-07-29 00:00:00
abstract::Human liver alanine aminopeptidase is inhibited by L-amino acids having hydrophobic side chains such as Phe, Tyr, Trp, Met, and Leu. Blocking of the amino group or the carboxyl group greatly reduces the inhibitory capacity of the amino acid. Kinetic studies demonstrate that inhibition of hydrolysis of the substrate L-...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00685a027
更新日期:1975-07-15 00:00:00
abstract::The method of transient electric birefringence has been applied to study the conformation of protein-sodium dodecyl sulfate complexes. A model of a deformable prolate ellipsoid has been proposed for the protein-dodecyl sulfate complex. This model is compared to the models proposed by J. A. Reynolds and C. Tanford (197...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00685a030
更新日期:1975-07-15 00:00:00
abstract::The properties of the homogeneous cutinase I, cutinase II, and the nonspecific esterase isolated from the extracellular fluid of cutin-grown Fusarium solani F. pisi (R.E. Purdy and P.E. Kolattukudy (1975), Biochemistry, preceding paper in this issue) were investigated. Using tritiated apple cutin as substrate, the two...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a007
更新日期:1975-07-01 00:00:00
abstract::The ionic and nucleotide requirements for the in vitro polymerization of microtubules from purified brain tubulin have been characterized by viscometry. Protein was purified by successive cycles of a temperature dependent assembly-diassembly scheme. Maximal polymerization occurred at a concentration of 0.1 M Pipes (pi...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a032
更新日期:1975-07-01 00:00:00
abstract::The complete amino acid sequence of a small, basic protein with cardiotoxic activity is described. This toxin, designated Naja naja F8, was isolated from the venom of Naja naja, of Cambodian origin, by gel filtration on Sephadex G-75 followed by gradient ion exchange chromatography on Bio-Rex 70. The cardiotoxin F8, m...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a011
更新日期:1975-07-01 00:00:00
abstract::In an effort to extend automated Edman degradation to nanomole quantities of protein, the method of sequenator analysis described by Edman and Begg (Edman, P., and Begg, G. (1967), Eur. J. Biochem. 1, 80) was modified to permit long degradations in the absence of carrier proteins. By using an aqueous 0.1 M Quadrol pro...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a036
更新日期:1975-07-01 00:00:00
abstract::The amino acid sequence of chick skin collagen alpha1-CB7, the 268 CNBr peptide from the helical portion of the alpha1 chain, has been determined by automatic and manual degradation of tryptic and chymotryptic peptides, and of the COOH-terminal fragment produced by cleavage with animal collagenase. The resulting seque...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a013
更新日期:1975-07-01 00:00:00
abstract::Dog serum and colostral immunoglobulin A (IgA) and free secretory component from colostrum were isolated using affinity chromatography. Both serum and colostral IgA showed similar susceptibility to reduction with dithiothreitol, but only colostral IgA released the additional subunit, bound secretory component. This re...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00684a010
更新日期:1975-07-01 00:00:00
abstract::L-alpha-Hydroxy acid oxidase (listed as EC 1.4.3.2, L-amino acid: O2 oxidoreductase) has been purified 100-fold from rat kidney to apparent homogeneity by gel electrophoresis. A subunit molecular weight of 47,500 was found by sodium dodecyl sulfate gel electrophoresis, but in contrast to previous reports, the enzyme h...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00683a005
更新日期:1975-06-17 00:00:00
abstract::The enzyme hydrogenase, from the photosynthetic bacterium Chromatium, was purified to homogeneity after solubilization of the particulate enzyme with deoxycholate. The purification procedure included ammonium sulfate fractionation, treatment with manganous phosphate gel, heating at 63 degrees, DEAE-cellulose chromatog...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00683a001
更新日期:1975-06-17 00:00:00
abstract::When stoichiometric amounts of tropomyosin (TM) are bound to F-actin in the presence of 2 mM ATP, the MG2+-activated acto-heavy meromyosin (HMM) ATPase is inhibited by about 60% in 5 mM MgCl2-30 mM KCl. If the concentration of MgCl2 is reduced to 1 mM, the inhibition disappears because TM no longer binds to F-actin. I...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00683a025
更新日期:1975-06-17 00:00:00
abstract::The fluorescence quenching of 9-aminoacridine (9AA) in suspension of beef heart EDTA submitochondrial particles was studied and was used to calculate the pH gradient between these particles and the medium. This pH gradient, which is energy dependent, is also dependent strongly on the presence of anion species in the m...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00683a017
更新日期:1975-06-17 00:00:00
abstract::The spontaneous hydrolyses of lactic acid O-phenyl phosphate (I) and, to a lesser extent, 3-hydroxybutyric acid O-phenyl phosphate (II) have been investigated and compared with similar intramolecular and bimolecular reactions. Compared to bimolecular nucleophilic reactions, the reactivity of II is similar to other sys...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00682a025
更新日期:1975-06-03 00:00:00
abstract::The phosphorylating of the lysine-rich histone at various stages in the cell cycle has been studied. In rapidly dividing cell populations the lysine-rich histone is phosphorylated rapidly after synthesis and more slowly once bound to the chromosome. The half-life of hydrolysis of such interphase phosphorylation in 5 h...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00682a033
更新日期:1975-06-03 00:00:00
abstract::The interaction of concanavalin A (Con A) with isolated adipocytes was studied using Con A-Sepharose beads in the affinity binding buoyant density method previously used to study insulin receptors. Free Con A-Sepharose beads could be separated from the bound beads (cell-bead complexes) by sedimentation of the high den...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00682a003
更新日期:1975-06-03 00:00:00
abstract::Proton nuclear magnetic resonance spectra of human hemoglobins in water reveal several exchangeable protons which are indicators of the quaternary structures of both the liganded and unliganded molecules. A comparison of the spectra of normal human adult hemoglobin with those of mutant hemoglobins Chesapeake (FG4alpha...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00682a036
更新日期:1975-06-03 00:00:00
abstract::The complete amino acid sequence was determined for bovine ubiquitin, and adenylate cyclase stimulating polypeptide, which is probably represented universally in living cells. Ubiquitin has a molecular weight of 8451 and consists of a single polypeptide chain containing 74 amino acid residues. It contains four argini...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00681a026
更新日期:1975-05-20 00:00:00
abstract::Acetylcholine receptors have been purified from junctional regions of normal rat diaphragm muscle and from extrajunctional regions of denervated diaphragm. The reaction of purified receptors with [122I]-alpha-bungarotoxin has been investigated by kinetic methods. The toxin-receptor complexes dissociated in a biphasic ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00681a008
更新日期:1975-05-20 00:00:00
abstract::The fluorescence decay of apoazurin derived from Pseudomonas aeruginosa is monoexponential. By this criterion the population of molecules of apoazurin is homogeneous. The emission anisotropy factor and the absorption anisotropy factor at the red edge of the absorption band assume similar values, showing that the trypt...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00680a018
更新日期:1975-05-06 00:00:00
abstract::Simple two-dimensional thin-layer chromatography was found to be useful for the separation of sugar methylated dinucleotides in RNA. Of the 16 possible sequences of the type Nm-Np, 15 were separated and all the sequences were determined. In a mouse hepatoma, MH 134, the levels of the sugar methylation in the 18S and 2...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00680a024
更新日期:1975-05-06 00:00:00
abstract::The dissociation of Semliki Forest virus induced by increasing concentrations of the anionic detergent sodium dodecyl sulfate was studied using density gradient centrifugation. Detectable binding to the virus started well below the critical micellar concentration of the detergent and increased thereafter with increase...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00680a005
更新日期:1975-05-06 00:00:00
abstract::A site-specific analog of ATP, 6,6'-dithiobis (inosinyl imidodiphosphate (S2P-PNP), inactivates the ATPase activities of myosin's proteolytic fragments, heavy meromyosin (HMM) and subfragment one (SF1), by formation of mixed disulfides between the 6 position of the purine ring and certain key cysteines. The stoichiome...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00680a015
更新日期:1975-05-06 00:00:00
abstract::Cells cultured from human skin synthesize precursor forms of types I and III collagens. After denaturation and reduction, the polypeptide chains obtained from these molecules had molecular weights estimated to be 140,000 and 120, 000. The larger chains, the pro alpha chains, are believed to be derived from the origina...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00679a007
更新日期:1975-04-22 00:00:00
abstract::Transcarboxylase is made up of a central hexameric subunit (S20,W similar 12 S), three peripheral dimeric metallo subunits (S20,W similar to 5 S), and six biotinyl carboxyl carrier subunits (S20,W similar to 1.3 S). The results presented here show that the carboxyl carrier subunit is required for assembly of the 12S a...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00679a010
更新日期:1975-04-22 00:00:00
abstract::The data and approach reported in paper I (Hanlon et al., 1975, preceding paper) have been used to calculate the fractional changes in secondary structure of calf thymus deoxyribonucleic acid which occur in aqueous solutions as a function of the concentration of NaCl, KCl, LiCl, CsCl, and NH4Cl. There is a continuous ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00679a018
更新日期:1975-04-22 00:00:00
abstract::The present paper reports a study on the equilibria and kinetics of the acid-alkaline transition and the azide binding reaction by ferric Aplysia myoglobin. A single completely reversible spectrophotometric titration curve is found over the pH range from similar to 5 to similar to 9, with an apparent pK equals to 7.5 ...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00679a006
更新日期:1975-04-22 00:00:00
abstract::Five gangliosides, accounting for over 95% of the total ganglioside fraction, were isolated from bovine adrenal medulla by preparative thin-layer chromatography and the carbohydrate structures determined by a combination of periodate oxidation and permethylation techniques. Partially methylated alditol acetates were g...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00678a026
更新日期:1975-04-08 00:00:00
abstract::The modified Tanford-Kirkwood electrostatic theory (Shire et al., 1974a) was applied to ferrimyoglobins from the following animal species: sperm whale (Physeter catodon), horse, California grey whale (Eschrichtius gibbosus), harbor seal (Phoca vitulina), and California sea lion (Zalophus californianus). Computations w...
journal_title:Biochemistry
pub_type: 杂志文章
doi:10.1021/bi00678a002
更新日期:1975-04-08 00:00:00