首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
The enzymatic deamination of 1,4-diaminobutane (putrescine) catalyzed by hog kidney diamine oxidase was studied with the aid of deuterium labeled substrates and mass spectrometry. An intermolecular deuterium isotope effect for the deamination of putrescine labeled with deuterium in all 4 alpha positions was observed to be 1.26. 1,4-Diaminobutane-1,1-d2 was synthesized and intramolecular isotope effects determined. The preference of diamine oxidase for the unlabeled alpha position was about 4 times greater than for the deuterated methylene. This work shows that intramolecular deuterium isotope effects are observable in enzyme systems other than cytochrome P-450.  相似文献   

2.
17-estradiol (E2) and progesterone (P) treatment of immature female rats (10 g/100 g body weight) respectively resulted in 1.38-fold (p<0.02) and 1.42-fold (p<0.02) increase in the uterine polyamine oxidase activity, and 2.45-fold (p<0.001) and 1.43-fold (p<0.02) increase in the uterine diamine oxidase activity, as compared to the controls. E2 caused a 5-fold (p<0.05) and a 1.36-fold (p<0.05) increase in putrescine and spermidine concentration respectively in rat uterus. Increases of 1.7-fold (p<0.02) and 1.6-fold (p<0.05) in putrescine and spermine concentration were determined in the P-treated uterus, as compared to the controls. The spermidine/spermine ratio, which is regarded as an index of growth rate, was higher in the E2-treated uterus and lower in the P-treated uterus than in the control uterus. No statistically significant hormonal effects were estimated in the immature liver. The data reported suggest the possibility of an involvement of polyamine-oxidizing enzymes in the modulation of polyamine concentrations in rat uterus by the female sex hormones.  相似文献   

3.
Summary Diamine oxidase from pea seedlings (PDAO) catalyzes the oxidation of 2-methyl-1,4-diaminobutane in a regioselective fashion, whereas diamine oxidase from pig kidney (KDAO) shows no regioselectivity for the same reaction.This work was supported by Ministero della Pubblica Istruzione. We thank Prof. A. Fiecchi and Prof. S. Ronchi for many helpful discussions.  相似文献   

4.
Summary Monoacetylcadaverine and monopropionylcadaverine were found to be substrates for both rat liver monoamine oxidase and hog kidney diamine oxidase, but all the Km-values for the oxidases were very high. The amines were common substrates for type A and type B monoamine oxidase.  相似文献   

5.
Summary An amine oxidase was purified 447-fold from soybean seedlings and some of its properties were investigated. The molecular weight of the enzyme was estimated to be 25,000. It was most active towards putrescine, followed by spermidine and spermine. Km-values for these substrates were relatively close. The enzyme was strongly inhibited by carbonyl reagents, such as semicarbazide and aminoguanidine.  相似文献   

6.
The novel polyamine derivatives sulphonamido oxa-spermine (oxa-Spm) and sulphonamido oxa-spermidine (oxa-Spd) exhibited rapid cytotoxic action towards MCF-7 human breast cancer cells with IC50 values of 4.35 and 6.47 μM, respectively, after 24-h drug exposure. Neither compound is a substrate of serum amine oxidase. Both oxa-Spm and oxa-Spd caused cell shrinkage, as determined by phase-contrast microscopy. After incubation with 10 μM of either compound for 8 h, the cells underwent chromatin condensation and nuclear fragmentation. However, no clear DNA ladder was obtained by electrophoresis. The sulphonamido oxa-polyamine derivatives and especially oxa-Spd enhanced the activity of polyamine oxidase (PAO), an enzyme capable of oxidising N1-acetylated spermine and spermidine to spermidine and putrescine, respectively, generating cytotoxic H2O2 and 3-acetamidopropanal as by-products. The intracellular polyamine content was only marginally reduced in response to drug treatment. In conclusion, our data show that these novel sulphonamido oxa-polyamine derivatives possess high cytotoxic activity against MCF-7 cells and indicate that induction of PAO may mediate their cytotoxicity via apoptosis. Received 17 January 2002; received after revision 22 February 2002; accepted 22 February 2002  相似文献   

7.
Summary Incubation of calf rib cartilage slices with antiproteoglycan serum elevates CO2-production, but inhibits biosynthesis of proteochondroitinsulfate and of total protein. Absorbing antiserum with proteoglycan abolishes these effects.Acknowledgment. This work was supported by grant K1 193/9 and 10 from the Deutsche Forschungsgemeinschaft.  相似文献   

8.
Summary During growth of young rats, monoamine oxidase activity in erythrocyte membrane preparations decreases more rapidly than reticulocyte concentrations in the respective blood samples. Since reticulocytes lose their mitochondria prior to the substantia reticulo-filamentosa, the non-linear correlation between monoamine oxidase activity and reticulocyte counts indicates that erythrocyte monoamine oxidase is located in reticulocyte mitochondria.This work was supported by a grant from the Deutsche Forschungsgemeinschaft.  相似文献   

9.
Summary Serum ceruloplasmin oxidase activity did not change in mice treated orally for 120 days with Li2CO3 (0.58 mEq/kg/day). After a single i.p. injection of LiCl (20 mEq/kg), a significant activation of ceruloplasmin was observed.R. R. A. is working with a research grant from the Conselho Nacional de Pesquisas (National Research Council of Brasil).  相似文献   

10.
Summary L1210 leukemic cells grown in vitro were subjected to kinetic analysis using a flow microfluorometer. A single broad peak was found for the DNA content distribution if unfractionated cells were used; prior fractionation using lg velocity sedimentation allowed the separation of small peaks with smaller (G1) and larger (G2) DNA contents from the dominant S phase peak with intermediate DNA content.This work was supported by grant number 5P01CA13053 awarded by the National Cancer Institute, DHEW USA, and by grant num ber RBI 76-1 from the Queen Wilhelmina Fund, The Netherlands.  相似文献   

11.
Summary Trypomastigote forms (infective) ofTrypanosoma cruzi incorporate (3H)-palmitic acid and D-(3H)-galactose into glycolipids. Palmitic acid-labeled acidic glycolipids were partially hydrolyzed with neuraminidase. The labeling of these compounds when the intact cell surface was labeled with galactose oxidase plus NaB3H4 indicates the membrane location of the sialoglycolipids.This investigation received financial support from SECYT and CONICET to RML; CNPq, FINEP, and UNDP/World Bank/ WHOSSpecial Programme for Research and Training in Tropical Diseases to WC; and FAPESP to BZ and WC. ASC is a fellow from FAPESP.  相似文献   

12.
Summary Isolated rat hearts were subjected to hypoxic perfusion on a recirculating Langendorff apparatus. Following a 30-min-period of aerobic stabilization the hearts were perfused for 30 min with media equilibrated with 84% N2, 12% O2 and 4% CO2. At the end of the hypoxic period myocardial concentrations of cyclic AMP and cyclic GMP were determined by radioimmunoassay. Exposure to hypoxia resulted in a significant increase in cyclic AMP (p<0.01) and a decrease in cyclic GMP (p<0.05) as compared to hearts perfused for 60 min with media gassed with 96% O2, 4% CO2.Acknowledgment. We gratefully acknowledge the excellent technical assistance provided by Mrs Inger O. Boggs and Miss Patricia C. Hannigan. This work was supported in part by U. S. Public Health Service grant HL 14661 from the National Heart and Lung Institute, and by a grant from the Central Ohio Heart Chapter.  相似文献   

13.
Summary Plasma T3, T4 and TSH levels in developing germfree rats were high, low and normal as compared with those in conventional counterparts. The high T3/T4 ratio in germfree rat plasma was lowered by cholestyramine feeding.This work was supported in part by a grant from the Imanaga Foundation, Nagoya, Japan.  相似文献   

14.
Summary Bilateral adrenalectomy in the rat results in an increase in heart monoamine oxidase activity in animals drinking water and in animals drinking 0.9% saline. Daily administration of deoxycorticosterone acetate prevented the increased monoamine oxidase activity in the animals drinking saline but not in those drinking water.Acknowledgment. This work was supported in part by a grant from the American Heart Association — Louisiana, Inc.  相似文献   

15.
Summary The synthetic estrogen diethylstilbestrol at a subinhibitory level of 1.75 g/ml diminished the production of staphylococcal alpha toxin, coagulase, deoxyribonuclease and penicillinase. Thus, the reported host beneficial effects of diethylstilbestrol may be partially related to its retardive action of certain toxins, or enzymes of S. aureus.Acknowledgments. This work was supported by United States Public Health Service, grant AI 06618, a grant in aid from Loyola University, United States Public Health Service, grant GRSG PRO 5368, and grants from Eli Lilly, Upjohn, Syntex, and G. D. Searle drug companies.  相似文献   

16.
Summary Part or all of the difference in the ability of ACTH1–24 and a fluorescent-labeled ACTH1–24 to activate lipolysis in fat cells can be accounted for by label-related binding to albumin present in the assay medium.Acknowledgments. We thank L. Hinman, B. Huber-Preston and C. Schatzmann for technical assistance, Drs P. Schiller and W. Rittel for the ACTH samples, and Dr T. Binkert for helpful discussion. This work was supported by the U.S. National Science Foundation (grant No. 18016) and by the Swiss National Science Foundation (grant No. 3589. 71).  相似文献   

17.
Summary Chloroperoxidase catalyzed the H2O2 oxidative conversion of N-methyl-4-chloroaniline to 4-chloronitrosobenzene, 4-chloroaniline and a mixture of complex products.This study was supported by grant No. CA 21992 from the National Cancer Institute, and by Research Career Development Award ES 00038 to M.D.C. from the National Institute of Environmental Health Sciences, DHEW.  相似文献   

18.
Summary Thromboxane B2 enhanced the beating frequency and the contractile tension of isolated rat atria. Both effects were inhibited by propranolol, by pretreatment with 6-hydroxydopamine, or after inhibition of prostaglandins synthesis with indomethacin and acetylsalicylic acid.This work has been supported by grant 6638 from CONICET (Argentina).  相似文献   

19.
Summary Homogenized mucosal linings prepared from vitamin A adequate and deficient male rats were used in metabolic studies of aflatoxin B1 (AFB1). Cytochrome P-420 was identified in both groups which metabolized AFB1 to 4 metabolic products in vitro. The implications of this observation are discussed in relation to colon carcinoma.Acknowledgments. This work was supported by USPHS (NIEHS), grant R01 ES 00336 and R01 CA 00270. Hoffman-La Roche Foundation Research Corporation awarded to T. C. C., Research Career Development Awardee of the NIEHS. Present address: Division of Nutritional Sciences, Cornell University, Ithaca, New York, USA.  相似文献   

20.
Summary Washed human platelets have been incubated with the lectins WGA, ConA and RCA1, adsorbed to differentsized gold particles. Plasma membrane receptors for each lectin were then located by scanning and transmission electron microscopy.Acknowledgments. We would like to thank Mlle Dominique Dupuis for technical assistance. This work was supported in part by grant No. CRL 78.5.128.1 from INSERM.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号