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1.
The respiratory quinone composition of the obligate methane-utilizing bacterium Methylomonas rubra was examined. A single lipoquinone was isolated which on examination by thin-layer chromatography cochromatographed with coenzyme Q. Reverse-phase partition and argentation high performance liquid chromatography demonstrated the lipoquinone did not correspond to any known coenzyme Q prenologue. On the basis of mass spectrometry and proton nuclear magnetic resonance spectrometry the novel lipoquinone was shown to correspond to 2,3-dimethoxy-5-methyl-6-(11-methylene-3,7,15, 18, 18, 19, 23-heptamethyltetracosa-2, 6, 14, 19, 22-pentaenyl-)-1,4-benzoquinone. 相似文献
2.
Summary The self-condensation of 2(3)-O-glycyl esters of adenosine, adenosine-5-(O-methylphosphate) and P1, P2-diadenosine-5-pyrophosphate in 6.2 mM solutions at pH 8.0 and -5°C in the presence of 12.5 mM poly(U) yields approximately 3 times as much diketopiperazine as reactions without poly(U). As the concentration of 2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate is decreased from 6.2 mM to 1.5 mM the yield of diketopiperazine in the presence of poly(U) decreases slightly from 6.6% to 5.2%, whereas, in the absence of poly(U) the yield of diketopiperazine decreases substantially from 2.4% to 0.75%. The enhanced yield of diketopiperazine that is attributed to the template action of poly(U) is temperature dependent and is observed only at temperatures below 10°C (5°C to -5°C) for 6.2 mM 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate) and below 23°C (15°C to -5°C) for 6.2 mM 2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate. The absence of a template effect at high temperatures is attributed to the melting of the organized helices. The hydrolysis half-lives at pH 8.0 and -5°C of 2(3)-O-(glycyl)-adenosine, 2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate), 2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate, and 5-O-(glycyl)-adenosine in the presence of poly(U) are substantially larger than their half-lives in the absence of poly(U). The condensation of 2(3)-O-(glycyl)-adenosine yields 5% of 5-O-(glycyl)-adenosine in the presence of poly(U) compared to 0.7% in the absence of poly(U).Abbreviations DKP
diketopiperazine
- (gly)2
glycylglycine
- (gly)3
glycylglycylglycine
- AppA-gly
2(3)-O-(glycyl)-P1, P2-diadenosine-5-pyrophosphate
- MepA-gly
2(3)-O-(glycyl)-adenosine-5-(O-methylphosphate)
- Ado-2(3)-gly
2(3)-O-(glycyl)-adenosine
- Ado-5-gly
5-O-(glycyl)-adenosine
- Boc-gly
N-tert-butyloxycarbonylglycine
- AppA
P1, P2-diadenosine-5-pyrophosphate
- MepA
adenosine-5-(O-methylphosphate)
- AppA-Boc-gly
2(3)-O-(Boc-glycyl)-P1, P2-diadenosine-5-pyrophosphate
- Ado-5-Boc-gly
5-O-(Boc-glycyl)-adenosine
- Ado-2(3)-Boc-gly
2(3)-O-(Boc-glycyl)-adenosine 相似文献
3.
The cleavage of adenosine-5-monophosphate (5-AMP) and guanosine-5-monophosphate (5-GMP) by Ce4+ and lanthanide complex of 2-carboxyethylgermanium sesquioxide (Ge-132) in acidic and near neutral conditions was investigated by NMR , HPLC and measuring the liberated inorganic phosphate at 37°C and 50°C. The results showed that 5-GMP and 5-AMP was converted to guanine (G), 5-monophosphate (depurination of 5-GMP), ribose (depurination and dephosphorylation of 5-GMP), phosphate and adenine (A), 5-monophosphate (depurination of 5-AMP), ribose (depurination and dephosphorylation of 5-AMP), phosphate respectively by Ce4+. In presence of lanthanide complexes, 5-GMP and 5-AMP were converted to guanosine (Guo) and phosphate and adenosine (Ado) and phosphate respectively. The mechanism of cleaving 5-GMP and 5-AMP is hydrolytic scission 相似文献
4.
Summary Soluble lead salts and a number of lead-containing minerals catalyze the formation of oligonucleotides from nucleoside 5-phosphorimidazolides. The effectiveness of lead compounds correlates strongly with their solubility. Under optimal conditions we were able to obtain 18% of pentamer and higher oligomers from ImpA. Reactions involving ImpU gave smaller yields.Abbreviations A
adenosine
-
U
uridine
-
Im
imidazole
-
MeIm
1-methyl-imidazole
-
EDTA
ethylenediaminetetraacetic acid
-
pA
adenosine 5-phosphate
-
pU
uridine 5-phosphate
-
Ap
adenosine cyclic 2:3-phosphate
-
ATP
adenosine 5-triphosphate
-
AppA
P1,P2-diadenosine 5-diphosphate
-
pNp (N = A,U)
nucleotide 2(3), 5-diphosphate
-
ImpA
adenosine 5-phosphoreimidazolide
-
ImpU
uridine 5-phosphorimidazolide
-
A
2pA
adenylyl-[25]-adenosine
-
A
3pA
adenylyl-[35]-adenosine
-
pA
2pA
5-phospho-adenylyl-[25]-adenosine
-
pA
3pA
5-phospho-adenylyl-[35]-adenosine
-
pUpU
5-phospho-uridylyl-uridine
-
pApU
5-phospho-adenylyl-uridine
-
pUpA
5-phospho-uridylyladenine
-
(pA)n (n, 2,3,4,)
oligoadenylates with 5 terminal phosphate
-
ImpApA
5-phosphorimidazolide of adenylyl adenosine
-
(pA)
5+
pentamer and higher oligoadenylates with 5 terminal phosphate
-
(Ap)nA (n = 2,3,4)
oligoadenylates without terminal phosphates
In the following we do not specify the nature of the internucleotide linkageIn the following we do not specify the nature of the internucleotide linkage 相似文献
5.
The six binary montmorillonite clay-catalyzed reactions of the5-phosphorimidazolides of adenosine, cytidine, guanosine anduridine were performed and the eight dimers from each reactionwere separated and analyzed by HPLC. A 16–51-fold higher yieldof the 5-purine-pyrimidine dimers over that of the5-pyrimidine-purines was observed. The total yield of the5-purine-pyrimidine dimers was in the 50–70% range while thatof the 5-pyrimidine-purine dimers was 1.3–7.0%. Less sequenceselectivity was observed in the homodimers formed.Regioselectivity for the formation of 3, 5-phosphodiesterbonds over that found in the absence of clay was observed. The5-purine-pyrimidine, 5-pyrimidine-pyrimidine and5-purine-purine dimers had 3, 5-links in about half of theirphosphodiester bonds. The percent phosphodiester links in the5-pyrimidine-pyrimidine dimers was 18%, a value close to thatobserved in the absence of the montmorillonite catalyst. Themontmorillonite-catalyzed reaction of all four activatednucleotides was performed and the 24 products were separated andanalyzed. The trends observed in the binary reactions wereconfirmed and the results also showed that the relativereactivity of the activated monomers was A>G>C>U in theratio 8.2: 4.8: 1.3: 1 respectively. No 5-pyrimidine-purineswith a 5-U and pG3pU, pC3pAand pC3pG weredetected. These studies suggest that a limited population ofRNAs would have formed in catalyzed prebiotic reactions. 相似文献
6.
Summary In pollen tubes, the motive force of cytoplasmic streaming is assumed to be generated by the sliding of the translocator associated with cell organelles along actin filaments. In the present study, the characteristics of the translocator were studied by reconstituting the movement of pollen tube organelles along characean actin bundles. Movement of pollen tube organelles proceeded from the pointed end to the barbed end of the actin filaments of the characean cells. The reconstituted movement was not inhibited by vanadate. KCL at higher concentrations inhibited the movement. Furthermore, heavy meromyosin (HMM) prepared from rabbit skeletal muscle myosin partially inhibited the reconstituted movement and pCMB-modified HMM inhibited it completely. The present results strongly support our previous conclusion that the translocator which generates the motive force of cytoplasmic streaming in pollen tube is myosin.Abbreviations AMP-PNP
adenylyl-imidodiphosphate
- ATP
adenosine-5-triphosphate
- ATP--S
adenosine-5-0-(3-thiotriphosphate)
- BSA
bovine serum albumin
- CCCP
carbonylcyanide m-chlorophenylhydrazone
- DTT
dithiothreitol
- EDTA
ethylenediamine tetraacetic acid
- EGTA
ethyleneglycol-bis-(-aminoethyl ether)N,N,N,N-tetraacetic acid
- HB
homogenization buffer
- HMM
heavy meromyosin
- NEM
N-ethylmaleimide
- pCMB
p-chloromercuribenzoic acid
- PIPES
piperazine-N,N-bis-(2-ethanesulfonic acid)
- PPi
pyrophosphate 相似文献
7.
Hans Kleinig Hans Reichenbach Hans Achenbach Jochen Stadler 《Archives of microbiology》1971,78(3):224-233
Summary The carotenoid pigments of the myxobacterium Sorangium compositum were analyzed by chromatographical and chemical techniques and by visible, infra red, and mass spectroscopy. Besides -carotene, neurosporene, torulene, lycopene, and 1,2-dihydro-1-hydroxy--carotene, four new carotenoid glycosides were found. These pigments were identified as 1,2-dihydro-1-hydroxy-torulene glucoside ester (I), 1,2-dihydro-3,1-dihydroxy-torulene glucoside ester (III), 1,2-dihydro-1-hydroxy-torulene rhamnoside (II), and 1,2-dihydro-3,1-dihydroxytorulene rhamnoside (IV).Fifth communication on the carotenoids of myxobacteria. Fourth communication see Arch. Mikrobiol. 76, 364–380 (1971). 相似文献
8.
Comparison of [35S]GTPγS binding to plasma membranes and endomembranes prepared from soybean and rat
Summary Plasma membranes were prepared from soybean hypocotyls and roots by aqueous two-phase partitioning and subsequent free-flow electrophoresis. The highly purified plasma membranes bound [35S]GTPS with a relatively high affinity (Kd10nM). The binding was saturable and specific as it was indicated by the displacement of bound [35S]GTPS by unlabeled GTPS and GTP, but not by ATPS, ATP, UTP or CTP. ITP was intermediate in its ability to displace [35S]GTPS. When soybean plasma membrane proteins were separated by SDS-PAGE and displayed by autoradiography, two major [35S]GTPS binding proteins were revealed with apparent molecular weights of 24 and 28 kDa. Results with plasma membranes from soybean hypocotyls and roots were similar but differed from those with plasma membranes prepared from rat liver and adipocytes where only a single major [35S]GTPS binding activity with a molecular weight of 28 kDa was observed.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- G
protein hetero-trimeric GTP binding protein with , , subunits
- Gn
protein GTP binding protein detected on nitrocellulose blots
- GTPS
guanosine 5-[-thio]triphosphate
- IAA
3-indoleacetic acid
- SDS-PAGE
sodium dodecylsulfate-polyacrylamide gel electrophoresis 相似文献
9.
ATPase activity in rat heart sarcoplasmic reticulum was stimulated in a concentration-dependent manner by both Ca2+ and Mg2+ in the complete absence of the other cation. Increasing concentrations of Mg2+ produced an apparent inhibition of the Ca2+-dependent ATP hydrolysis. CDTA (trans-1,2-diaminocyclohexane-N,N,N,N-tetraacetate) had no effect on these responses. The results indicate the presence of a low affinity non-specific divalent cation-stimulated ATPase in rat heart sarcoplasmic reticulum. However, sarcoplasmic reticulum vesicles transported Ca2+ with a high affinity (K0.5 Ca2+ = 0.41 M) suggesting the presence of a high affinity Ca2+-transporting ATPase. Calmodulin did not stimulate rat heart sarcoplasmic reticulum ATPase activity over a range of Ca2+ and Mg2+ concentrations and failed to stimulate membrane phosphorylation and Ca2+ transport into sarcoplasmic reticulum vesicles. Calmodulin antagonists trifluoperazine and compound 48180 did not affect the ATPase activity. Catalytic subunit of cAMP-dependent protein kinase was also ineffective in stimulating the ATPase activity. These results suggest the presence of an ATPase activity in rat heart sarcoplasmic reticulum with different properties from the high affinity Ca2+-pumping ATPase previously characterized in dog heart and other species.Abbreviations cAMP
adenosine 3,5-monophosphate
- CaM
calmodulin
- CDTA
trans-1,2-diaminocyclohexane-N,N,N,N-tetraacetate
- EDTA
ethylene-diaminetetraacetate
- EGTA
ethylene glycol bis(-aminoethyl ether)-N,N,N,N-tetraacetate
- PLB
phospholamban
- SR
sarcoplasmic reticulum
- TFP
trifluoperazine 相似文献
10.
Toshikazu Oki Akihiro Yoshimoto Tatsuo Ogasawara Seiji Sato Akira Takamatsu 《Archives of microbiology》1976,107(2):183-187
The occurrence of adenosine 5-triphosphate-3-diphosphate-synthesizing activity was detected in five strains of actinomycetes; Streptomyces morookaensis, Streptomyces aspergilloides, Streptomyces hachijoensis, Actinomyces violascens and Streptoverticillium septatum, out of 825 strains of actinomycetes, bacteria, fungi and imperfecti. Purine nucleotide pyrophosphotransferase were extracellularly excreted associating with the cell growth, and were purified partially or to apparent homogeniety from the culture filtrate. The enzymes are a monomeric protein with a molecular weight of 18000–26000 and synthesize adenosine, guanosine and inosine 5-phosphate (mono, di or tri)-3-diphosphate such as pApp, ppApp, pppApp, pGpp, ppGpp, pppGpp and pppIpp by transferring a pyrophosphoryl group from the 5-position of ATP, dATP and pppApp to the 3-position of purine nucleotides in the presence of a divalent cation and in alkaline state.Abbreviations pppApp
adenosine 5-triphosphate 3-diphosphate
- ppApp
adenosine 5-diphosphate 3-diphosphate
- pApp
adenosine 5-monophosphate 3-diphosphate
- pppGpp
guanosine 5-triphosphate 3-diphosphate 相似文献
11.
Summary In this first article on the carotenoids of Myxobacterales we report on the minor carotenoids of Stigmatella aurantiaca: phytoene, phytofluene, lycopene, -carotene, 4-keto--carotene, 1,2-dihydro-1-hydroxy--carotene, 4-keto-1,2-dihydro-1-hydroxy--carotene, 4-keto-1,2-dihydro-1-hydroxy-torulene, and 1,2,1,2-tetrahydro-1,1-dihydroxy-lycopene. These pigments account for about 10% of total carotenoids. 相似文献
12.
Partial purification of myosin from lily pollen tubes by monitoring with in vitro motility assay 总被引:1,自引:0,他引:1
Summary Myosin in pollen tubes ofLilium longiflorum was partially purified, using an in vitro motility assay as a monitor. The main components in the partially purified preparation had molecular masses of 110, 120, and 140 kDa in SDS-PAGE. They became bound to actin filaments in an ATP-dependent manner. Among the components, only that of 120 kDa became bound to ATP and was concluded to be the heavy chain of pollen tube myosin.Abbreviations ATP
adenosine-5-triphosphate
- DTT
dithiothreitol
- EB
extraction buffer
- EGTA
ethyleneglycol-bis-(-aminoethylether) N, N, N, N-tetraacetic acid
- PAGE
polyacrylamide gel electrophoresis
- PIPES
piperazine-N,N-bis-(2-ethanesulfonic acid)
- PMSF
phenylmethylsulfonyl fluoride
- SDS
sodium dodecylsulfate
- TBS
Tris buffered saline
- TEB
Tris-EGTA buffer 相似文献
13.
Plausible prebiotic conditions for the phosphorylation of nucleosides by inorganic phosphate were reported by Lohrmann and Orgel in 1971. This reaction was carried out on heated dry films and promoted by urea. The major products formed were nucleoside-2:3 cyclicPs; 5-NMPs and other derivatives were also formed. Minor modifications of the Lohrmann and Orgel system have resulted in the preferential formation of 5-NMPs. In this modified system a 2-fold preference for phosphorylation of the 5-OH group over the 3(2)-OH group was observed and the formation of other derivatives was minimized. The small amounts of bis compounds that were formed in this system could be quantitatively removed by selective binding to the mineral hydroxylapatite at moderate ionic strengths. It was also discovered that under hydrolytic conditions there was a 3:1 preference for removal of phosphates attached to the 3-OH group over the 5-OH group. A recycling procedure for obtaining additional 5-NMPs from bis compounds and 3-NMPs is proposed. 相似文献
14.
Summary Amino acids are activated by reaction with adenosine 5-phosphorimidazolide in aqueous imidazole buffers. If adenosine 5-(O-methylphosphate), an analogue of the 3-terminus of t-RNA is present, 2(3)-O-aminoacyladenosine 5-(O-methylphosphate) is formed. Fifteen percent of this compound accumulated at pH 5.8, but less was formed at higher pHs. The highest efficiency of utilization of ImpA attained in our experiments was about 24%. Analogous reactions occured with several other amino acids, including a number that have functional side-chains.Abbreviations pA
adenosine 5-monophosphate
- MepA
adenosine-5-(O-methylphosphate)
- ImpA
adenosine-5-phosphorimidazolide
- A
adenosine
- MepA-ala
2(3)-O-alanyl-adenosine-5-(O-methylphosphate)
- ala-N-pA
adenylyl-(5 N)-alanine
- ImH
imidazole
- DKP
diketopiperazine 相似文献
15.
Summary The absence of the methyl substituent at the 2position of the cyclohexene ring of TCHP enhances the conversion rate as well as the yields of the 3-hydroxy product obtained byStreptomyces natalensis and the 3-keto product obtained byMycobacterium smegmatis.Abbreviations TCHP
1-(2-thienyl)-3-(1-cyclohexen-1-yl)-1-propanone
- TCHP-OH
1-(2-thienyl)-3-(3-hydroxyl-1-cyclohexen-1-yl)-1-propanone
- TCHP-ketone
1-(2-thienyl)-3-(1-cyclohexen-1-yl-3-one)-1-propane
- TMCHP
1-(2-thienyl)-3-(2-methyl-1-cyclohexen-1-yl)-propanone 相似文献
16.
Claudia P. Spampinato Piotr Paneth Marion H. O'Leary Carlos S. Andreo 《Photosynthesis research》1991,28(2):69-76
Structural analogues of the NADP+ were studied as potential coenzymes and inhibitors for NADP+ dependent malic enzyme from Zea mays L. leaves. Results showed that 1, N6-etheno-nicotinamide adenine dinucleotide phosphate ( NADP+), 3-acetylpyridine-adenine dinucleotide phosphate (APADP+), nicotinamide-hypoxanthine dinucleotide phosphate (NHDP+) and -nicotinamide adenine dinucleotide 2: 3-cyclic monophosphate (23NADPc+) act as alternate coenzymes for the enzyme and that there is little variation in the values of the Michaelis constants and only a threefold variation in Vmax for the five nucleotides. On the other hand, thionicotinamide-adenine dinucleotide phosphate (SNADP+), 3-aminopyridine-adenine dinucleotide phosphate (AADP+), adenosine 2-monophosphate (2AMP) and adenosine 2: 3-cyclic monophosphate (23AMPc) were competitive inhibitors with respect to NADP+, while -nicotinamide adenine dinucleotide 3-phosphate (3NADP+), NAD+, adenosine 3-monophosphate (3AMP), adenosine 2: 5-cyclic monophosphate (25AMPc), 5AMP, 5ADP, 5ATP and adenosine act as non-competitive inhibitors. These results, together with results of semiempirical self-consistent field-molecular orbitals calculations, suggest that the 2-phosphate group is crucial for the nucleotide binding to the enzyme, whereas the charge density on the C4 atom of the pyridine ring is the major factor that governs the coenzyme activity.Abbreviations NADP+
1, N6-etheno-nicotinamide adenine dinucleotide phosphate
- NHDP+
nicotinamide-hypoxanthine dinucleotide phosphate
- APADP+
3-acetylpyridine-adenine dinucleotide phosphate
- SNADP+
thionicotinamide-adenine dinucleotide phosphate
- AADP+
3-aminopyridine-adenine dinucleotide phosphate
- 23NADPc+
-nicotinamide adenine dinucleotide 2: 3-cyclic monophosphate
- 3NADP+
-nicotinamide adenine dinucleotide 3-phosphate
- 2AMP
adenosine 2-monophosphate
- 3AMP
adenosine 3-monophosphate
- 23AMPc
adenosine 2: 3 monophosphate cyclic
- A
adenosine
- RuBP
ribulose 1,5-bisphosphate
- SCF-MO
Self-Consistent Field-Molecular Orbitals (method) 相似文献
17.
A. D. Dmitriev O. N. Danilevskaya R. B. Khesin 《Molecular & general genetics : MGG》1976,145(3):317-326
Summary The influence of mutations in structural genes of and subunits of RNA polymerase upon the synthesis of these subunits in E. coli cells have been investigated. An amber-mutation ts22 in the subunit gene decreases the intracellular concentration of this subunit and the rate of its synthesis. At the same time the concentration and the rate of subunit synthesis is increased. These suggest the compensatory activation of the RNA polymerase operon that takes place under the conditions of shortage of one of the subunits. Reversions, as well as more effective supression of ts22 amber mutation, achieved by streptomycin addition, substitution of su2 by su1, or by specific mutations, result in a rise of and drop of subunit concentration and synthesis in ts22 mutant.
TsX missense-mutation in the subunit gene alters the properties of the enzyme increasing, at the same time, the concentration and the rate of synthesis of both and subunits, particularly at a nonpermissive temperature. This points to an inversely proportional relationship between the rate of synthesis of RNA polymerase subunits and the total intracellular activity of the enzyme. Extra subunits are rapidly degraded in ts22 and tsX mutants.The whole complex of our data and those of others suggest that the regulation of the synthesis of RNA polymerase subunits is accomplished by interaction of a negative and a positive mechanisms of regulation which include not only activators and repressors but the enzyme itself as well. 相似文献
18.
J. P. Ferris H. Yanagawa W. J. Hagan Jr. 《Origins of life and evolution of the biosphere》1984,14(1-4):99-106
Diiminosuccinonitrile (DISN), formed by the oxidation of diaminomaleonitrile (DAMN), has been investigated as a potential prebiotic phosphorylating agent. DISN effects the cyclization of 3-adenosine monophosphate to adenosine 2, 3-cyclic phosphate in up to 39% yield. The mechanism of this reaction was investigated. The DISN-mediated phosphorylation of uridine to uridine monophosphate does not proceed efficiently in aqueous solution. The reaction of DISN with uridine-5-phosphate and uridine results in the formation of 2,2-anhydronucleotides and 2,2-anhydronucleosides respectively, and other reaction products resulting from an initial reaction at the 2- and 3-hydroxyl groups. The clay mineral catalysis of the cyclization of adenosine-3-phosphate was investigated using homoionic montmorillonites. 相似文献
19.
A. G. Green 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,72(5):654-661
Summary The inheritance of two mutants of flax (Linum usitatissimum), having altered proportions of the C18 polyunsaturated fatty acids, linoleic and linolenic, was examined. Both lines, M1589 and M1722, are homozygous for a single gene mutation which reduces linolenic acid content from 34% to 22% and raises linoleic acid from 15% to 27%. Genetic analysis of crosses involving M1589, M1722 and their parental cultivar Glenelg revealed that these mutations are in different unlinked genes and exhibit additive (codominant) gene action. The symbolsLn1 andLn2 are proposed for the mutated genes in M1589 and M1722, respectively. Recombinant genotypes homozygous for the mutant alleles at both loci are very low in linolenic acid (2%) and high in linoleic acid (48%), with unaltered proportions of other fatty acids. The complete inverse correlation between linoleic and linolenic acids (r=-0.98) indicates that the mutations block the synthesis of linolenic acid at the linoleic desaturation step. 相似文献
20.
Summary Cyclic nucleotide phosphodiesterase in the basal-lateral segment of plasma membranes from proximal tubule cells of the rabbit renal cortex was studied and compared to that in the brush border segment of the plasma membrane. Both adenosine 3,5-monophosphate and guanosine 3,5-monophosphate were hydrolyzed by the basal-lateral membrane, but activity varied differently with the two substrates in a complex concentration-dependent manner. Activity with adenosine 3,5-monophosphate was greater than, equal to, or less than with guanosine 3,5-monophosphate, at concentrations of 1000, 100, and 10 to 1 m, respectively. Basal-lateral membrane phosphodiesterase activities at 1 and 500 m substrate exhibited differential responses to pH, metals, heat, and a heat stable inhibitor. Stimulation by guanosine 3,5-monophosphate and inosine 3,5-monophosphate of adenosine 3,5-monophosphate hydrolysis was found in basal-lateral but not in brush border membranes. This stimulation was potentiated by ethyleneglycol-bis(-aminoethyl ether)N,N-tetraacetic acid and ethylenediaminetetraacetate, inhibited by Triton X-100, and totally blocked by Zn2+. The findings indicate that multiple forms of phosphodiesterase are present in the basal-lateral segment and these differ from the activities in the brush border region of the plasma membrane. The characteristics of (i) allosteric, guanosine 3,5-monophosphate-sensitivity of adensoine 3,5-monophosphate phosphodiesterase, and (ii) relatively high guanosine 3,5-monophosphate phosphodiesterase activity, in basal-lateral membranes, which are also enriched in adenylate and guanylate cyclase, suggest an important physiological role for these phosphodiesterases in the regulation of net production of cyclic nucleotides in the renal cortex. 相似文献