Showing papers on "Alkaline phosphatase published in 1975"
TL;DR: π�80 transducing phages for the proC †, phoA and phoB genes of Escherichia coli have been obtained, in agreement with a positive control mechanism for the regulation of alkaline phosphatase synthesis.
501 citations
TL;DR: None of the activities appear to have a requirement for Ca-2-+, and hence would not seem to be involved with active Ca- 2-+ transport in the typical manner, and the concept that the Mg-2+-ATPase and pyrophosphatase activities of matrix vesicles stem from one enzyme, namely, alkaline phosphatase is consistent.
279 citations
TL;DR: Although the rat K- NPPase appeared almost completely insensitive to ouabain with this cytochemical medium, parallel studies with the more glycoside-sensitive rabbit kidney indicated that K-NPPase activity in these nephron segments is sensitive to this inhibitor.
Abstract: A cytochemical method for the light and electron microscope localization of the K- and Mg-dependent phosphatase component of the Na-K-ATPase complex was applied to rat kidney cortex, utilizing p-nitrophenylphosphate (NPP) as substrate. Localization of K-N-ATPase activity in kidneys fixed by perfusion with 1% paraformaldehyde -0.25% glutaraldehyde demonstrated that distal tubules are the major cortical site for this sodium transport enzyme. Cortical collecting tubules were moderately reactive, whereas activity in proximal tubules was resolved only after short fixation times and long incubations. In all cases, K-NPPase activity was restricted to the cytoplasmic side of the basolateral plasma membranes, which are characterized in these neplron segments by elaborate folding of the cell surface. Although the rat K-NPPase appeared almost completely insensitive to ouabain with this cytochemical medium, parallel studies with the more glycoside-sensitive rabbit kidney indicated that K-NPPase activity in these nephron segments is sensitive to this inhibitor. In addition to K-NPPase, nonspecific alkaline phosphatase also hydrolyzed NPP. The latter could be differentiated cytochemically from the specific phosphatase, since alkaline phosphatase was K-independent, insensitive to ouabain, and specifically inhibited by cysteine. Unlike K-NPPPase, alkaline phosphatase was localized primarily to the extracellular side of the microvillar border of proximal tubules. A small amount of cysteine-sensitive activity was resolved along peritubular surfaces of proximal tubules. Distal tubules were unreactive. In comparative studies, Mg-ATPase activity was localized along the extracellular side of the luminal and basolateral surfaces of proximal and distal tubules and the basolateral membranes of collecting tubules.
197 citations
TL;DR: A phylogenetic comparison of enzyme levels in animal and human PMN was undertaken; marked interspecies differences in enzyme activity were found; many species were deficient in alkaline phosphatase or lysozyme.
192 citations
TL;DR: Host cell and virus-specific poly(A)-containing RNAs isolated from nuclei and cytoplasm of monkey kidney cells infected with simian virus 40 contain different methylated nucleotides and the possible role of methylation in the processing and translation of simianirus 40-specific mRNA is discussed.
Abstract: Host cell and virus-specific poly(A)-containing RNAs isolated from nuclei and cytoplasm of monkey kidney cells infected with simian virus 40 contain different methylated nucleotides. In the cytoplasmic simian virus 40-specific RNA, about 75% of the radioactivity derived from (methyl-3-H)methionine was in N-6-methyladenosine (N-6mA) after digestion with Penicillium nuclease and bacterial alkaline phosphatase. The remainder was in a negatively charge component with properties of 5'-terminal structures, i.e., digestion with nucleotide pyrophosphatase and bacterial alkaline phosphatase released 2'-O-methyladenosine (A-m), 2'-O-methylguanosine (G-m), and 7-methylguanosine (m-7-G), consistent with a 5'-terminal structure of the type, m7-GpppNm. The nuclear virus-specific RNA contained N6mA, GM, 2'-O-methyluridine (U-m), and a smaller proportion (10%) of nuclease-, phosphatase-resistant presumptive 5' termini that also yielded A-m, G-m, and m7-G upon further hydrolysis. The infected cell nuclear and cytoplasmic RNAs that did not hybridize to DNA of simian virus 40 contained all four 2'-O-methylnucleosides. The possible role of methylation in the processing and translation of simian virus 40-specific mRNA is discussed.
167 citations
TL;DR: It appears that accommodation of E. coli to the presence of Cd2+ involves exclusion of the ion from the cell and reversal of damage caused by prior exposure to the ion, which is reversible and does not appear to result from a selection of mutant cells.
Abstract: Cells of Escherichia coli strain B develop large intracellular vacuoles and exhibit an abnormally long lag phase when inoculated into a defined medium to glucose and salts containing 3 times 10-6 M Cd2+. Early in this lag, about 95% of the cells fail to form colonies when plated on nutrient broth-NaCl-agar. Prior to the initiation of proliferation, the morphology of these cells becomes normal. They regain viability in the absence of deoxyribonucleic acid replication. The rate and extent of growth are normal once proliferation begins. This reversible phenomenon of accommodation to a growth-inhibiting concentration of Cd2+ does not appear to result from a selection of mutant cells. Cells which are proliferating in the presence of Cd2+ accumulate the ion to a very high concentration. In membranes and 31% in the cytoplasm. In unaccommodated cells, the figures are 2%, 75%, and 23%, respectively. The activity of alkaline phosphatase, a zinc-metalloenzyme which is inhibited by cadmum and is located between cell wall and membrane, is not abnormally low in accommodated cells, suggesting that the cadmim is compartmentalized in these cells. Molecular sieve chromatography of cell extracts shows that the Cd2+ is associated with two classes of macromolecules. It appears that accommodation of E. coli to the presence of Cd2+ involves exclusion of the ion from the cell and reversal of damage caused by prior exposure to the ion.
148 citations
TL;DR: Several organic phosphate esters could replace inorganic phosphate for growth and were also hydrolyzed by the partially purified enzyme, but growth rates were characteristically lower and the specific activity only 3 to 4 fold higher than in cultures grown in phosphate excess.
Abstract: Anacystis nidulans (Synechococcus) was maintained in a medium of low phosphate concentration (0.1 mM) and grew with a normal doubling time of 5 hrs at 30°C. Such cultures ahd a normal pigment composition and alkaline phosphatase was detectable at low specific activities only.
127 citations
TL;DR: This method has the advantage of taking into account quantitative variations in the heat stability characteristics of liver alkaline phosphatase from one sample to another, in contrast to methods in which only a single period of exposure to 56 degrees C is employed.
126 citations
TL;DR: Type of phosphodiesterases can be conveniently distinguished by their ability to hydrolyze phosphonate esters, which are preferable to the more conventional esters of nucleotides and bis(4-nitrophenyl) phosphate because of their superior stability and ease of synthesis.
Abstract: 4-Nitrophenyl and 2-napthyl monoesters of phenylphosphonic acid have been synthesized, and an enzyme catalyzing their hydrolysis was resolved from alkaline phosphatase of a commerical calf intestinal alkaline phosphatase preparation by extensive ion-exchange chromatography, chromatography on L-phenylalanyl-Sepharose with a decreasing gradient of (NH4) 2SO4, and gel filtration. Detergent-solubilized enzyme from fresh bovine intestine was purified after (NH4)2SO4 fractionation by the same technique. The purified enzyme is homogeneous by polyacrylamide gel electrophoresis and sedimentation equilibrium centrifugation. It has a molecular weight of 108,000, contains approximately 21% carbohydrate, and has an amino acid composition considerably different from that reported from alkaline phosphatase from the same tissue. The homogeneous intestinal enzyme, an efficient catalyst of phosphonate ester hydoolysis but not of phosphate monoester hydrolysis, was identified as a 5'-nucleotide phosphodiesterase by its ability to hydrolyze 4-nitrophenyl esters of 5'-TMP but not of 3'-TMP. Also consistent with this identification was the ability of the enzyme to hydrolyze 5'-ATP to 5'-AMP and PPi, NAD+ to 5'-AMP and NMN, TpT to 5'-TMP and thymidine, pApApApA to 5'-AMP, and only the single-stranded portion of tRNA from the 3'-OH end. Snake venom 5'-nucleotide phosphodiesterase also hydrolyzes phosphonate esters, but 3'-nucleotide phosphodiesterase of spleen and cyclic 3',5'-AMP phosphodiesterase do not. Thus, types of phosphodiesterases can be conveniently distinguished by their ability to hydrolyze phosphonate esters. As substrates for 5'-nucleotide phosphodiesterases, phosphonate esters are preferable to the more conventional esters of nucleotides and bis(4-nitrophenyl) phosphate because of their superior stability and ease of synthesis. Furthermore, the rate of hydrolysis of phosphonate esters under saturating conditions is greater than that of the conventional substrates. At substrate concentrations of 1 mM the rates of hydrolysis of phosphonate esters and of nucleotide esters are comparable and both superior to that of bis(4-nitrophenyl) phosphate.
124 citations
TL;DR: Quenching of the phosphoenzyme formed under steady state conditions with [32P]AMP as a substrate as well as stopped flow analysis of the catalyzed hydrolysis of 2,4-dinitrophenyl phosphate or p-nitrophenol phosphate have shown that the two active sites of the native and of the Mg2+-stimulated enzyme are not equivalent.
112 citations
TL;DR: It is indicated that phenobarbital therapy is associated with improvement in organic anion clearance in some patients with cholestatic disorders and may be beneficial to such patients.
Abstract: Fifteen patients with cholestatic disorders were treated for 1 to 5 months with phenobarbital. Primary biliary cirrhosis was diagnosed in seven, sclerosing cholangitis in two, intrahepatic biliary hypoplasia in three, and cholestatic hepatitis in three. Except for the patients with cholestatic hepatitis, in whom marked cholestasis was virtually the only abnormality in liver biopsy specimens, serum bilirubin and bile acid concentrations were diminished during therapy, the hepatic clearance of sulfobromophthalein and 131-I-rose bengal was variably enhanced, and there was relief from pruritus. Serum cholesterol concentrations and other measures of hepatic function were not significantly changed during therapy except for serum alkaline phosphatase activity, which rose in twelve patients. Parallel changes occurred in 5'-nucleotidase, suggesting a hepatic origin for the alkaline phosphatase activity. These studies indicate that phenobarbital therapy is associated with improvement in organic anion clearance in some patients with cholestatic disorders and may be beneficial to such patients.
TL;DR: The l-p-bromotetramisole is introduced as a potent inhibitor of non-specific alkaline phosphatase and is recommended also as an additive for specific phosphatases media in order to yield the specific activity only.
Abstract: A levamisole analogue, the l-p-bromotetramisole is introduced as a potent inhibitor of non-specific alkaline phosphatase.
TL;DR: An enzyme electrode which senses oxygen consumption for the assay of phosphate ion was constructed by using two enzymes together, which caused a smaller and slower oxygen consumption which could be detected by a platinum disc electrode at -0.6 V vs. SCE amperometrically.
TL;DR: It is concluded that the vesicles correspond to fragments of the liver cell membranes that appear and continue to circulate in the blood of patients with cholestasis.
TL;DR: The role of magnesium and other metal ions in regulatory processes, only now beginning to be explored fully, will likely emerge as an important avenue for achievement of regulatory effects in metalloenzymes.
Abstract: Alkaline phosphatase of E. coli, isolated by procedures which do not alter its intrinsic metal content, contains 1.3 +/- 0.3 g-atom of magnesium and 4.0 +/- 0.2 g-atom of zinc per molecule of molecular weight 89,000. Magnesium, the role of which has been unappreciated, significantly affects the function and structure of alkaline phosphatase containing either 2 or 4 g-atom of zinc per mole. Magnesium does not activate the apoenzyme but increases the activity of the enzyme containing 2 g-atom of zinc 4.4-fold and that of the enzyme containing 4 g-atom 1.2-fold. The results obtained with enzyme in which cobalt is substituted for zinc are analogous. Moreover, the absorption and electron paramagnetic resonance spectra of cobalt phosphatases reveal the effects of magnesium on cobalt coordination geometry. Addition of magnesium changes the spectral characteristics of the apoenzyme reconstituted with 2 g-atom of cobalt from predominantly octahedral to 4- or 5-coordinate geometry. These two classes of cobalt binding sites have been associated with catalysis and structure stabilization, respectively. Therefore, magnesium controls the occupancy of the catalytic and structural binding sites and modulates the resultant enzymatic activity. Hydrogen-tritium exchange was employed to determine the effects of magnesium on the conformational stability of phosphatase. Magnesium stabilizes the dynamic structural properties, both of apophosphatase and of enzyme containing 2 g-atom of zinc, which is further stabilized by 2 more zinc atoms. The role of magnesium and other metal ions in regulatory processes, only now beginning to be explored fully, will likely emerge as an important avenue for achievement of regulatory effects in metalloenzymes.
TL;DR: There was no clear evidence that pregnancy as such led to increased vitamin-D requirement in any case of these groups, and the levels in the vegetarian Asians were lower than in the other two groups.
TL;DR: Tissue specimens studied from patients with male pattern alopecia revealed the presence of miniature or vellus follicles; a marked enlargement of the sebaceous glands and arrectores pilorum muscles; and the thinning of the dermis.
Abstract: Three hundred and forty-seven tissue specimens were studied from 23 patients with male pattern alopecia. Characteristic features of pattern alopecia included: the presence of miniature or vellus follicles; a marked enlargement of the sebaceous glands and arrectores pilorum muscles; the presence of connective tissue streamers beneath the vellus follicles; and the thinning of the dermis. A mild perivascular infiltrate of mononuclear cells and mild capillary dilatation was sometimes seen. An increased number of mast cells was often a prominent feature. Histochemical procedures were performed for glycogen, acid mucosaccharides, inorganic substances, and enzymes including alkaline phosphatase, acid phosphatase, beta glucuronidase, cholinesterase, aminopeptidase, oxidases and dehydrogenases. Histochemical studies did not reveal any significantly abnormal enzyme changes other than the altered vascular and nerve supply to the the miniature follicles.
TL;DR: Data concerning amino acid composition, sugar content, enzyme stability, absorbance index, and sedimentation velocity is presented, which indicates that the alkaline phosphatase is a dimer comprising two very similar or identical subunits of about 87,000 molecular weight.
Journal Article•
TL;DR: Incubation of diphosphonate with several enzymes demonstrated inhibition of acid and alkaline phosphatase activity but showed no effect on glutamic oxalacetic transaminase and lactate dehydrogenase activity.
Abstract: Enzymes have been proposed as tissue receptors that bind 99mTc-stannous diphosphonate and its analogs. Incubation of diphosphonate with several enzymes demonstrated inhibition of acid and alkaline phosphatase activity but showed no effect on glutamic oxalacetic transaminase and lactate dehydrogenase activity. Complete reversal of the diphosphonate-induced inhibition of alkaline phosphatase activity occurred when calcium ion was added to the reaction. The specificity of calcium to induce reversal was dispelled when magnesium ion gave identical results. Diphosphonate-induced inhibition of acid phosphatase, however, was not reversed by calcium or magnesium.
TL;DR: In chronically diabetic animals, cell membranes may showsignificant changes in overall composition with no significant changes in the rate of protein turnover, but in control animals, this may not be the case.
Abstract: We have examined the effect of chronic diabetes mellitus upon cell membrane composition and turnover in streptozotocin-treated rats and control animals maintained for four to eight weeks. Liver plasma membranes, prepared from diabetic animals, showed enhanced activities of alkaline phosphatase and glucose-6-phosphatase and depressed 59-nucleotidase when compared with controls. Studies of the nonprotein constituents of liver plasma membranes and red cell “ghosts” showed similar changes in both tissues: sialic acid and cholesterol content were reduced in the membranes of diabetic animals, while phospholipids (total and individual classes) and neutral sugars were unchanged. To look for changes in relative turnover rates of individual membrane proteins, we combined a double-label in-vivo technic using [ 3 H] and [ 14 C] leucine with polyacrylamide gel separation of membrane proteins. No significant differences were observed between control and diabetic animals. In chronically diabetic animals, cell membranes may show significant changes in overall composition with no significant changes in the rate of protein turnover.
TL;DR: Alkaline phosphatase was solubilized from isolated plasma membranes and the kinetic properties of the enzyme are not markedly altered by its dissociation from the membrane matrix, however, there are significant differences in its behavior toward Mg2+ which suggest a structural role for Mg 2+ in liver alkalineosphatase.
TL;DR: It is concluded that hypoinsulinism has differential effects on the 3 fiber types in heterogeneous rat skeletal muscle, and that slow-twitch fibers are least affected by the diabetic condition.
Abstract: The response of rat gastrocnemius muscle fibers to chronic streptozotocin-diabetes was studied. Transverse sections of this muscle from normal and diabetic rats were histochemically assayed for reduced diphosphopyridine nucleotide-diaphorase, myofibrillar adenosine triphosphatase, mitochondrial alpha-glycerophosphate dehydrogenase, beta-hydroxybutyrate dehydrogenase, and alkaline phosphatase activities. Cross-sectional areas of the fiber types were measured, and fiber capillarization and populations estimated. Chemically-induced diabetes appeared to have little effect on the metabolic or morphological properties of slow-twitch fibers. However, a general dedifferentiation occurred in the 2 fast-twitch fiber populations. There was a loss of oxidative potential in the fast-twitch-oxidative-glycolytic fibers, and a significant decrease in size in the fast-twitch-glycolytic fibers. No change in the proportions of slow- and fast-twitch fibers in the muscles of diabetic rats occurred. It is concluded that hypoinsulinism has differential effects on the 3 fiber types in heterogeneous rat skeletal muscle, and that slow-twitch fibers are least affected by the diabetic condition.
TL;DR: Glycylprolyl β-naphthylamidase activities in sera from 40 normal subjects (18–81 years) were 22.6 ± 0.9 (S.E.) (11.8–38.2) I.U./l serum at 37°C, and the enzyme activities did not differ significantly with age between the younger group under 40-years-old and the older group over 40- years-old.
Journal Article•
TL;DR: It appears that focal changes in surface as well as in cytoplasmic and nuclear enzymes are intimately and very early linked to the carcinogenic process.
Abstract: Male Wistar rats were given 50 mug of aflatoxin B1 twice a week for 4 weeks, and thereafter 75 mug twice a week for 10 weeks. Their livers were investigated histologically and histochemically for glycogen, RNA, fat, alkaline and acid phosphatases, adenosine triphosphatase, 5'-nucleotidase, glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, succinic dehydrogenase, and alkaline and acid nucleases. No significant lesions occurred before 15 weeks. During this period, the liver was histochemically unchanged except for a periportal decrease of alkaline phosphatase and adenosine triphosphatase. Scattered hepatocytes with a strong glucose-6-phosphatase activity appeared. These changes represent toxic effects of aflatoxin B1 and are irrelevant to carcinogenesis. From 15 weeks onward, three types of liver cell hyperplastic foci and nodules developed. Histologically, and with respect to glycogen, fat, and RNA content, only two of these types were considered as potential precursors of hepatocarcinomas. However, all types exhibited a decrease or absence of the enzymes studied. Both histological and histochemical changes stressed the complex heterogeneity existing between and within hepatic foci and nodules. From 11 months on, hepatocarcinomas developed. The tumors disclosed similar histochemical changes. This similarity further supports the "precarcinomatous" nature of hyperplastic foci and nodules. It appears that focal changes in surface as well as in cytoplasmic and nuclear enzymes are intimately and very early linked to the carcinogenic process. Whether they are fundamental or only represent an epiphenomenon remains unclear.
TL;DR: An enzyme capable of hydrolyzing the substrate L-alanine p-nitroanilide has been found in the various Escherichia coli strains tested and is constitutively produced but the differential rate of synthesis is increased 4-fold when the cell growth is limited by Pi.
Abstract: An enzyme capable of hydrolyzing the substrate L-alanine p-nitroanilide has been found in the various Escherichia coli strains tested. This enzyme has been called aminoendopeptidase since it shows both activities (see accompanying paper). It is released from the cells by osmotic shock and by lysozyme -- EDTA spheroplasting treatment, and 50% of the total activity is directly detectable with suspensions of intact cells. However, the release by osmotic shock or spheroplasting is not as efficient as it is for alkaline phosphatase. This periplasmic aminoendopeptidase is constitutively produced but the differential rate of synthesis is increased 4-fold when the cell growth is limited by Pi. The occurrence of this 'derepression' is simultaneous with that of alkaline phosphatase. Increasing the concentration of inorganic phosphate in the medium has no effect on the constitutive aminoendopeptidase synthesis. The effect of phosphate starvation is specific since starvation for neither nitrogen nor carbon and energy source are effective in derepressing aminoendopeptidase.
TL;DR: Plasma membranes were isolated from rat liver mainly under isotonic conditions and it is suggested that the light fraction was derived from the bile front of the liver cell surface and the heavy one contained the blood front and the lateral surface of it.
TL;DR: It was demonstrated that the abnormal pattern found in a patient with skeletal abnormalities due to multiple epiphyseal dysplasia was caused by complex formation between serum alkaline phosphatase and immunoglobulin G of the lambda class and that the patient's immunoglOBulin G had the ability to bind the hepatic and osseous isoenzymes selectively but not to bile, placental and intestinal isoenZymes.
TL;DR: The course of the decline in alkaline phosphatase activity during exposure of serum samples to a temperature of 56 degree C can be resolved into two phases that represent the exponential decay of an enzyme component with an average half-inactivation time of 112 seconds.
TL;DR: Three phenotypes of placental alkaline phosphatase with different electrophoretical mobility exhibited identical immunological reactions with their respective antisera, which can be used for an immunological determination of these two alkali phosphatases without contamination by other alkalineosphatases in human serum.
TL;DR: At 24 days, when maturation of the intestinal epithelium normally culminates, the intestine is disproportionately small, and Sucrase activity appears in the jejunum, and maltase activity increases slightly, but both activities are less than a third of those in intact animals at 24 days.