Showing papers in "Biochimica et Biophysica Acta in 1969"

TL;DR: A general rate equation has been derived and shown to be quadratic with square and linear terms in v which represents that true initial steady-state velocity of enzymic reactions that are reversibly inhibited by a substrate analogue at concentrations comparable to that of the enzyme.

TL;DR: The model proposes competitive dissipation of absorbed energy by photochemical trapping at reaction centers and by fluorescence and radiationless de-excitation from both the pigment bed and reaction centers of System 2.

TL;DR: Factors indicate that the pre-illumination of pigment system II changes the efficiency of excitation transfer between chlorophyll a molecules and the fluorescence yields at liquid nitrogen temperature.

TL;DR: High resolution nuclear magnetic resonance (NMR) spectroscopy has been used to study the spectra of the common bile acids in organic solvents, the structure of the bile-salt micelle and the interaction of bile salt with lecithin in mixed micelles, consistent with the hypothesis that the leCithin-bile salt micelle exists as a bilayer of lecitin surrounded on its hydrophobic surfaces by bile salts.

TL;DR: Human erythrocyte glutathione reductase (NAD(P)H) was purified 47 000-fold by column chromatography and full restoration of the activity did not guarantee that the original enzyme conformation had been acquired.

TL;DR: The facts indicate that Mg2+ controls the distribution of excitation energy between the two pigment systems and that the control consists mainly in change in rate ofexcitation transfer from the bulk chlorophyll a molecules in pigment system II to those in pigmentSystem I.

TL;DR: In the 25–60 age group neither the hexuronic acid nor the total hexosamine contents showed any correlation with the age of the subject, however, there was considerable local variation and variation between individuals.

TL;DR: In the presence of 3-ketosteroids, the rates of penetration of glycerol were significantly higher than those containing 3β-hydroxy steroids, and Cholesterol-depleted erythrocytes also exhibited considerably increased Glycerol permeability.

TL;DR: A new method has been developed for the partial synthesis of saturated, unsaturated and mixed-acid lecithins using the free O-(sn-glycero-3-phosphoryl) choline and its CdCl2 complex as starting materials.

TL;DR: A hydroxamic acid (aerobactin) is excreted by cultures of Aerobacter aerogenes 62-1 and related strains when growing in an iron-deficient medium.

TL;DR: The final (Na+-K+)-stimulated ATPase membrane is relatively free of brush border, mitochondria, nuclear and microsomal contamination and would appear to be plasma membrane, and is discussed in relation to active transport in the intestine.

TL;DR: The membrane contains protein complexes which can be dissociated by sodium dodecyl sulfate after exposure to salt, and the dissociation is less extensive when intact membranes are exposed to salt.

TL;DR: The results are discussed in terms of the electrostatic interaction between positive charges on lysozyme and negative charges on the cell wall, that are absent from the oligosaccharides from chitin.

TL;DR: Findings support the concept of the separate existence of cytochromes a and a3, and indicate that cytochrome a and the EPR-undetectable copper are titrated first, at which point ferricy tochrome a3 becomes detectable by EPR.

TL;DR: The two porcine lipases appear to be very closely related with regard to amino acid composition, molecular weight and specific activity on long- or short-chain triglycerides.

TL;DR: Two anti-H(O) phytohemagglutinins have been separated by (NH4)2SO4 fractionation of extracts of Ulex europeus seeds and one was found to be inhibited by L-fucose and the other was inhibited most by di-N-acetylchitobiose.

TL;DR: Observations strongly suggest that Cl− acts near the water-splitting end of Photosystem II, and with the current model of the chloroplast fluorescence quenching mechanism, the effect of Cl− was examined on the photooxidation of reducing agents which are capable of donating electrons to Photos System II.

TL;DR: Guanyl cyclase was assayed by determining the rate of conversion of GTP to cyclic 3′,5′-[ 32 P]GMP, which showed a pH optimum near 7.6 and was dependent on Mn 2+ .

TL;DR: The crude protein fraction of human duodenal contents catalyzed the formation of ceramide from sphingomyelin most efficiently at slightly alkaline pH in the presence of conjugated bile salts, indicating that the enzymes are of intestinal origin.

TL;DR: Results were taken as evidence that the synthesis of PRPP in the erythrocytes is governed primarily by the P i -dependent catalytic capacity ofPRPP synthetase, wherease the rate-limiting role of the intracellular supply of Rib-5- P manifest itself only when the optimum requirement of the system for P i had been satisfied.

TL;DR: The standard physiological free energy changes of reactions of glycolysis, the reductive pentose phosphate cycle and the oxidative pentoses phosphate cycle have been calculated from available data, finding that most of the negative free energy change occurring under steady-state conditions in this metabolic system is dissipated for purposes of control.

TL;DR: The results indicate that CO 2 and O 2 in vivo both act as electron acceptors of photosynthesis; O 2 reduction probably supplies ATP in a pseudocyclic type of photo-phosphorylation and does not seem to fit into a model with separate and independent photoreactions.

TL;DR: It is probable that the glutathione peroxidase can catalyse the reduction of the hydroperoxides of all the polyunsaturated fatty acids that occur in subcellular membranes.

TL;DR: Results are compatible with an activation by preincubation, detergents and UDP-N-acetylglucosamine due to exposition of active sites of glucuronyltransferases that have been nonfunctioning in unactivated tissue homogenates.

TL;DR: Investigation of the relative incorporation of a number of radioactive fatty acids into the different glycerolipids of rat liver microsomes showed that in all three lipids, the majority of the saturated fatty acids were at the 1-position while the polyunsaturated fatty acids are largely confined to the 2-position.

TL;DR: The results obtained using the Goodrich and collapse pressure methods are in good agreement and the most pronounced effect was observed for dilauroyl leCithin and oleoyl-stearoyl lecithin.

TL;DR: In this article, the authors examined mixtures of prostaglandins E1 and E2 at different concentrations and found that the relationship between the extent of platelet aggregation, expressed in percentages of the maximum decrease in absorbance in the control (% max. Δ A), and the molar concentration, can be written as: %max. ΔA = −494 −99 log [PGE1 + 26 log[PGE2]

TL;DR: A purified protein kinase obtained from rabbit skeletal muscle catalyzed the conversion of transferase I to transferase D and activated phosphorylase b kinase (phosphorylases b kin enzyme kinase activity) and catalyzing the phosphorylation of casein.

TL;DR: Methods which permit permeability coefficients of 4% phosphatidic acid-phosphatidyl choline liposomes to be measured over the region 1· 10−9-1 · 10−13 cm · sec−1 have been developed and are described.

TL;DR: The method has been utilized to determine the concentration of dTTP in HClO 4 extracts of mouse leukemia cells and Streptococcus faecalis and offers the advantages of simplicity, speed, and sensitivity.