Blood clearance ofMS2 bacteriophage inSalmo trutta: a paradoxon

Summary A primary challenge ofMS2 bacteriophage was cleared from the blood of the teleostSalmo trutta within 2.5 days. In contrast the clearance of a 2nd challenge required an extra 3.5 days and the induction of the secondary antibody response was delayed, though immune memory was observed later.     

Partial purification of a plasma-kinin-forming enzyme from horse urine

Zusammenfassung Durch Chromatographie mit Diäthylamino-äthyl-cellulose nach Ammoniumsulfat-Fraktionierung wurde ein Plasma-Kinin-freisetzendes Ferment aus Pferdeharn teilweise (80×) gereinigt. Das so gereinigte Präparat war gegen Pferde-, Menschen-, Rinder (Fraktion IV-4)- und Ratten-Blutplasma, nicht aber gegen Schweine-(Fraktion IV-4)-Globuline wirksam. Durch Sojabohnen-Trypsininhibitor oder Ovomucoid erfolgt keine Hemmung. Präparate von verschiedenem Reinheitsgrad zeigten entsprechendep-Toluenesulfonyl-l-arginin-methylester-spaltende und Kinin-freisetzende Wirksamkeit.

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Read before the XIIth Annual Meeting of the Sociedade Brasileira para o Progresso da Ciência, Piracicaba, July 1960; supported by Grant No. 58217 from the Rockefeller Foundation.     

Formation of carthamin by a partially purified enzyme from safflower seedlings

Summary An enzyme responsible for synthesizing carthamin from precarthamin was partially purified and the catalytic properties were investigated.Acknowledgments. The authors wish to thank Prof. A. Komamine, University of Tokyo, for reading this paper. We are indebted to Prof. A. Saito, Tokai University, for performing emission spectrochemical analysis of the enzyme protein used in this study.     

On the regulatory properties of a halophilic malic enzyme from Halobacterium cutirubrum.

The NADP-linked malic enzyme from Halobacterium cutirubrum is strongly inhibited by acetyl-CoA and NADH, and rather weakly inhibited by oxaloacetate and glyoxylate, in the presence of very high KCl concentrations (3 M), considered physiological for the extremely halophilic bacteria.     

Quantification of digoxin by enzyme immunoassay: synthesis of a maleimide derivative of digoxigenin succinate for enzyme coupling

Summary We synthesized the m-maleimidobenzoyl derivative of digoxigenin-3-0-succinate (through a p-phenylenediamine bridge) as a hapten derivative directed towards coupling to sulfhydryl groups of -galactosidase. Prepared enzyme conjugate had about 97% of the enzyme labeled with the hapten derivative while retaining full enzyme activity. The enzyme immunoassay for digoxin we prepared showed a maximum sensitivity of 30 pg per assay (c.v.=3%) with minimal cross-reaction with digotoxin (3.8%). Our method for hapten conjugation to -galactosidase is highly efficient and is simple and easily replicated.     

Protein methylase from calf liver nuclei: enzyme characterization and stimulation by serum albumins.

A protein methylase from calf-lifer nuclei was partially purified by sonication of the nuclear pellet at high ionic strength, chromatin removal and ammonium sulphate fractionation of the solubilized activity.     

Determinant of efficiency of a monomeric enzyme: Acceleration by site-specific molecules for trypsin

Summary The interaction of a specific ligand at substrate binding site was shown to be responsible for the catalytic efficiency of trypsin. The reasoning of induced fit theory was refined by kinetic analysis of characteristic properties of inverse substrates.This work was supported by grants from the Ministry of Education, Science and Culture, Japan.     

The effects of hydrocortisone and glycyrrhizine on the enzyme releases of arylsulfatase and hyaluronidase from lysosomes of liver

Hydrocortisone and glycyrrhizine act as both stabilizers and labilizers of the lysosomes of liver. The effect of both agents on the lysosomes is changeable according to the duration of their administration.     

The effects of hydrocortisone and glycyrrhizine on the enzyme releases of arylsulfatase and hyaluronidase from lysosomes of liver

Summary Hydrocortisone and glycyrrhizine act as both stabilizers and labilizers of the lysosomes of liver. The effect of both agents on the lysosomes is changeable according to the duration of their administration.     

Determinant of efficiency of a monomeric enzyme: acceleration by site-specific molecules for trypsin.

The interaction of a specific ligand at substrate binding site was shown to be responsible for the catalytic efficiency of trypsin. The reasoning of 'induced fit' theory was refined by kinetic analysis of characteristic properties of 'inverse' substrates.     

Transthyretin: a review from a structural perspective

Transthyretin (formerly called prealbumin) plays important physiological roles as a transporter of thyroxine and retinol-binding protein. X-ray structural studies have provided information on the active conformation of the protein and the site of binding of both ligands. Transthyretin is also one of the precursor proteins commonly found in amyloid deposits. Both wild-type and single-amino-acid-substituted variants have been identified in amyloid deposits, the variants being more amyloidogenic. Sequencing of the gene and the resulting production of a transgenic mouse model have resulted in progress toward solving the mechanism of amyloid formation and detecting the variant gene in individuals at risk. Received 23 January 2001; received after revision 4 April 2001; accepted 30 April 2001     

The membrane component of the ribosomal bodies from the lizardLacerta sicula: a freeze-etching study

Summary We have studied, using the freeze-etching technique, the cytomembranes of the flat cystenae, regularly interposed between the cristalline sheets of ribosomes, inside the ribosomal bodies of the hibernating lizardLacerta sicula. The results show the presence, on the protoplasmic face (PF), of numerous IMPs (intramembrane particles) which can be separated into two populations. The flatter ones appear to be arranged in a regular pattern, with the support of the optical diffraction analysis, can be correlated with the disposition of the ribosomes in the cristalline sheets.6 October 1986     

The bisphosphonates HEBP and AHPrBP but not AHBP inhibit mineral mobilization and lysosomal enzyme release from mouse calvarial bones in tissue culture

The effect of 3 bisphosphonates, 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP), 3-amino-1-hydroxy-propylidene-1, 1-bisphosphonate (AHPrBP) and azacycloheptylidene-2, 2-bisphosphonate (AHBP), on the release of minerals (40Ca, 45Ca, Pi) and enzymes from cultured mouse calvaria was investigated in an organ culture system. HEBP and AHPrBP reduced PTH-stimulated mobilization of calcium and inorganic phosphate without affecting the release of lactate dehydrogenase. In contrast, no significant effect by AHBP on mineral mobilization and lysosomal enzyme release could be registered. In parallel with inhibited mineral mobilization, HEBP and AHPrBP inhibited the release of the lysosomal enzyme beta-glucuronidase. A possible cellular mechanism of action of bisphosphonates is discussed in the light of these data.     

The bisphosphonates HEBP and AHPrBP but not AHBP inhibit mineral mobilization and lysosomal enzyme release from mouse calvarial bones in tissue culture

Summary Mice injected with DSP-4 [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine], a selective noradrenergic neurotoxin, had marked depletions of central noradrenaline and an attenuated post-decapitation reflex. DSP-4-treated mice exhibited an increased sensitivity to the ₂-adrenoceptor agonist clonidine as measured by inhibition of the pinna reflex, but normal sensitivity as measured by hypothermia. This differential sensitivity may reflect the presence of supersensitive postsynaptic ₂-adrenoceptors in some, but not all, CNS regions after DSP-4 treatment.Acknowledgments. The authors gratefully acknowledge the excellent technical assistance of Mr P. E. Richards. DSP-4 hydrochloride and clonidine hydrochloride were synthesized by Beecham Pharmaceuticals Research Division.