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PubMed2000

[UV-B comb versus betamethasone solution in scalp psoriasis].

BACKGROUND: The aim of the study was to assess the effectiveness of a UV-B-comb on scalp psoriasis versus betamethasone valerate solution. MATERIAL AND METHODS: Of 44 adult patients with scalp psoriasis, 22 were treated with a dermalight 80 psoracomb and 22 with betamethasone valerate solution, five times a week for three weeks. RESULTS: No difference in effect was found at the end of treatment. Two weeks after end of treatment a higher proportion of patients treated with UV-B-comb (7/22) had remained in remission than those treated with betamethasone valerate solution (3/22; p < 0.05). INTERPRETATION: Treatment with a UV-B-comb offers a good alternative to topical corticosteroids for patients with scalp psoriasis.

Administration, Topical↗

PubMed2001

[High-level production of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by feb-batch culture of Alcaligenes eutrophus].

Fermentation strategies for production P (3HB-co-3HV) from glucose and propionic (or valeric) acid by Alcaligenes eutrophus were studied. During the culture, we controlled pH of the broth by feeding precusors of 3HV- propionic or valeric acid after Ammonia feeding stopped. When propionic acid were used as the precusor, for 50 hours, we obtained a cell dry weight, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content and a 3HV fraction of 149.9 g/L, 124.9 g/L, 83.3% and 12.4 mol%, respectively, with a PHA productivity of 2.50 g h-1 L-1. When valeric acid were used as the precusor, for 45 hours, we obtained a cell dry weight, a P(3HB-co-3HV) concentration, a P(3HB-co-3HV) content and a 3HV fraction of 160.2 g/L, 119.0 g/L, 74.2% and 17.7 mol%, respectively, with a PHA productivity of 2.64 g h-1 L-1. Prior to this study, it hasn't been reported to obtain such high level productivity and 3HV fraction at the same time by Alcaligenes eutrophus.

3-Hydroxybutyric Acid↗

PubMed1992

Two new combinations of estrogen and progestogen for prevention of postmenopausal bone loss: long-term effects on bone, calcium and lipid metabolism, climacteric symptoms, and bleeding.

Bone mass, calcium and lipid metabolism, climacteric symptoms, bleeding, blood pressure, and weight changes were studied in 62 healthy postmenopausal women at 3-month intervals throughout 2 years of treatment with continuous estradiol valerate (2 mg) plus cyproterone acetate (1 mg), sequential estradiol valerate (2 mg) plus levonorgestrel (75 micrograms), or placebo. During the 2 years of the study, bone mineral content of the distal and ultradistal regions of the forearm (measured by single-photon absorptiometry) remained unchanged in the hormone groups, whereas bone mineral content at these sites decreased by 5 and 6%, respectively, in the placebo group. Bone mineral density in the spine (measured by dual-photon absorptiometry and dual-energy x-ray absorptiometry) increased by 3-4% in the hormone groups and decreased by 2% in the placebo group. Biochemical estimates of bone turnover (serum alkaline phosphatase and fasting urinary calcium/creatinine) decreased significantly to premenopausal levels in the hormone groups, but remained unchanged in the placebo group. Serum concentrations of total and low-density lipoprotein cholesterol were significantly reduced by 5-10% (P less than .05-.01) in the estradiol + cyproterone acetate group and by 10-15% (P less than .001) in the estradiol valerate + levonorgestrel group. There were no significant changes in high-density lipoprotein cholesterol in the hormone groups. Virtually no changes were observed in the placebo group. Climacteric symptoms and hot flushes were significantly reduced in both hormone groups compared with the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Density↗

PubMed1979

Effects of estrogen to alter amino acid transport in R3230AC mammary carcinomas and its relationship to insulin action.

The effects of estrogens on transport and incorporation of amino acids into the R3230AC mammary adenocarcinoma were studied in vivo and in vitro. Dissociated tumor cells from ovariectomized rats, like those from diabetic rats, displayed elevated transport of proline, representing entry by the A system; transport of phenylalanine (L system) was unaltered, as was glucose transport and its utilization. Administration of estradiol valerate decreased the entry of proline into tumor cells from intact, diabetic, or ovariectomized animals; the response to the steroid hormone was greater in ovariectomized or diabetic rats compared to intact animals. The time course of the effects of estrogen treatment was examined in diabetic rats. By 72 hr, transport of both proline and leucine was significantly decreased; incorporation of leucine into proteins and uridine into RNA was significantly reduced by 24 hr after injection of estradiol valerate. The effects of estrogen in vivo to reduce transport of amino acids and their incorporation into proteins appeared to correlate with the reduced tumor growth observed. Experiments were performed to examine the effects of 17 beta-estradiol in vitro on amino acid transport into dissociated cells from ovariectomized or diabetic rats. Under these experimental conditions, 17 beta-estradiol (10(-6)M) inhibited proline transport with little or no effect on leucine transport in cells from ovariectomized rats; in cells from diabetic rats, proline transport and leucine incorporation were significantly reduced by estradiol, whereas phenylalanine transport was slightly inhibited (approximately 20%). The effect of estradiol in vitro was also manifest in tumor cells obtained from diabetic rats treated in vivo with estradiol valerate; estradiol in vitro caused a further reduction in proline transport but not in leucine transport, results that imply some specificity to the action of estrogen on the A system. Since we had earlier shown that insulin action on transport in these tumor cells were directed towards the A system, we examined the effects of insulin, estradiol, and their combination in vitro on proline and leucine transport. Insulin (10(-8) M) stimulated proline transport; 17 beta-estradiol, at a selected lower level of 10(-8) M, inhibited proline transport. When both were added in vitro, estradiol (10(-8 M) was capable of significantly reducing the insulin (10(-8) M)-induced increase in proline transport. Leucine transport was not altered in any of these experiments. Together, these data suggest that estrogens are capable of inhibiting amino acid transport into the R3230AC mammary carcinoma, an effect that is compatible with reduced tumor growth. The possible relationship of estrogen and insulin at the level of amino acid transport remains to be elucidated.

Adenocarcinoma↗

PubMedDate not supplied

Urinary magnesium in early postmenopausal women. Influence of hormone therapy on calcium.

The urinary excretion of magnesium was studied in two groups of healthy women just after menopause. The women in group I were randomly allocated to receive either placebo or 4, 2 or 1 mg 17 beta-oestradiol in cyclical combination with 1 mg norethisterone acetate (a progestational agent). Oestradiol was given, in the above-mentioned doses, from days 1 to 22, and 1, 1 or 0 mg oestradiol was given from days 23 to 28, in combination with norethisterone acetate from days 13 to 22 and oestriol 2, 1 or 0.5 mg from days 1 to 23 and 0.5, 0.5 or 0 mg from days 23 to 28. The women in group II were allocated to receive either placebo, 2 mg oestradiol valerate in cyclical combination with 1 mg cyproterone acetate (oestradiol valerate from days 1 to 21 and cyproterone acetate from days 12 to 21) with 1,000 mg of calcium per day or oestradiol valerate + cyproterone acetate without calcium. Oestrogen and progesterone therapy decreased the urinary magnesium excretion significantly when compared to the placebo group. The effect was related to the dose of oestrogen. Furthermore, our results indicate that calcium supplementation influences the urinary excretion of magnesium in a two-phase paradoxical manner.

Calcium↗

PubMed1986

Low-density lipoprotein as a carrier of antitumoral drugs: in vivo fate of drug-human low-density lipoprotein complexes in mice.

Previous studies have demonstrated that human leukemic cells and certain cancer cells in culture have a higher uptake of plasma low-density lipoprotein (LDL) than the corresponding normal cells. Therefore LDL has been proposed as a drug carrier for anticancer agents. In the present investigation, we have developed a method to incorporate a lipophilic derivative of doxorubicin, N-trifluoroacetyladriamycin-14-valerate, into LDL. The method involves lyophilization of LDL in the presence of sucrose as protective agent and gives an N-trifluoroacetyladriamycin-14-valerate-LDL complex containing about 100 drug molecules per LDL particle. The in vivo fate of the complex in mice as judged from the disappearance from plasma and accumulation in organs was similar to that of native LDL. When cultured human fibroblasts were incubated with N-trifluoroacetyladriamycin-14-valerate-LDL, cellular drug accumulation was dependent on the LDL receptor activity of the cells. The covalent linkage of two anthracycline derivatives to lysine residues of LDL yielded conjugates with drug/LDL molar ratios ranging up to 80. With increasing substitution, there was a progressive decline in the affinity of the conjugate for the LDL receptor in vitro. The in vivo fate of such conjugates was quite similar to that of native LDL. We conclude that it is possible to associate cytotoxic agents with LDL without interfering with its in vivo behavior.

Animals↗

PubMed1986

Flow cytometric monitoring of cellular anthracycline accumulation in murine leukemic cells.

Cellular accumulation of daunorubicin (DNR), N-trifluoroacetyl-adriamycin-14-valerate, and THP-Adriamycin (THP-ADR) in doxorubicin sensitive and resistant murine leukemic P388 cells was studied with laser excited flow cytometry. Appearance of DNR fluorescence in P388/S cells was rapid in contrast to that of P388/R cells. A comparison of P388/S and P388/R cells incubated for 20-30 min showed that DNR fluorescence in P388/R cells was one-sixth that of P388/S cells. In contrast, the difference between fluorescence value of P388/S and P388/R cells similarly incubated with N-trifluoroacetyl-adriamycin-14-valerate or THP-ADR was less than 2-fold. Chlorpromazine, verapamil, and trifluoperazine increased the cellular accumulation and cytotoxicity of DNR and THP-ADR but had no major effect on N-trifluoroacetyl-adriamycin-14-valerate fluorescence or cytotoxicity in P388/R cells. Fluorometric and soft agar assays confirmed the data on the effect of these modulators on drug accumulation obtained by the more rapid method of laser flow cytometry.

Animals↗

PubMed1985

Effects of new N-alkyl analogues of adriamycin on in vitro survival and cell cycle progression of L1210 cells.

The effects of N-benzyladriamycin-14-valerate (AD198) and N,N-dimethyladriamycin-14-valerate (AD199), two novel lipophilic N-alkyl derivatives of Adriamycin (ADR), on cell growth and cell cycle distribution were investigated in L1210 cells grown in suspension. Following a 1-h exposure to the drug levels selected, growth inhibition was noticeable in all cultures for most or all of the observation period of 96 h. With flow cytometry, an asynchronous cell population was measured with respect to cellular DNA, RNA, and light scatter (size) properties following a 1-h incubation with the various ADR analogues. In addition, flow cytometric techniques were utilized to determine whether drug treatment altered the sensitivity of DNA in situ to acid-induced denaturation or to binding by small DNA-intercalating dyes. Unlike the parent compound ADR or its DNA-nonbinding derivative N-trifluoroacetyladriamycin-14-O-hemiadipate (AD143), the N-alkyl derivatives AD198 and AD199 only slightly affected L1210 cell cycle traverse over the first 5 h posttreatment. However, by 24 h, AD199 (0.62 micrograms/ml) caused an S- and G2 + M-phase accumulation which became more dramatic at 48 and 72 h. AD198 (3.27 micrograms/ml) also caused an accumulation of cells predominantly in G2 + M phase at longer culture times (48 to 96 h). The two half-substituted congeners N-benzyladriamycin (AD288) and N,N-dimethyladriamycin (AD280) affected L1210 cell cycle traverse over a similar time scale at concentrations of 12.3 and 4.17 micrograms/ml, respectively. AD280 blocked cells in G1 and G2 + M whereas AD288 caused predominantly a G2 + M accumulation. While neither ADR nor AD143 interfered appreciably with binding and fluorescence of the intercalating dye acridine orange, all of the N-alkyl analogues tested reduced the fluorescence signal of acridine orange-stained L1210 cells by 26 to 60%. This effect lasted, with decreasing intensity, for at least 48 h following a 1-h exposure to the drugs. In addition, while ADR appeared to stabilize DNA in situ against acid-induced denaturation, all N-alkyl derivatives, to varying degrees, tended to increase DNA denaturability. Thus alkylation at the glycoside amine combined with the lipophilic 14-valerate side chain function accounts for several new biochemical and biological properties of AD198 and AD199, relative to ADR.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1978

[Ephedrine, salsoline and cytisine derivatives as substrates and inhibitirs of cholinesterases].

25 iodomethylates of acetic, propionic, butyric, isobutyric and valeric esters of N-(beta-hydroxyethyl)-derivatives of ephedrine (I) pseudo-ephedrine (II), salsoline (III), salsolidine (IV) and cytisine (V) are studied as substrates and inhibitors of acetylcholine esterase (EC 3.1.1.8) from human erythrocytes and butyrylcholine esterase (EC 3.1.1.8) from horse serum. Butyrylcholine esterase found to increase the hydrolysis rate of all the alkaloid esters studied with the increase of acyl radical either to valerates (for ephedrine and pseudo-ephedrine derivatives), or to butyrates (for the rest alkaloids) and then it did not considerably change under further elongation of carbon chain up to valerate. Isobutyrates were observed to be similar to propionates in their hydrolysis rates. Acetylcholine esterase hydrolyzed acetates with the highest rate, while butyrates of ephedrine and pseudoephedrine derivatives were hydrolyzed by the enzyme 2,5-3-fold as slow as acetates. The rate of choline esterase hydrolysis decreased in the row: ephedrine--salsoline--cytisine with the volumetric increase of the cationic group. The decrease was almost 10-fold for butyrylcholine esterase, while a transition from "poor" substrates to reversible inhibitors was observed for acetylcholine esterase (3 of 5 cytisine esters were reversible inhibitors of the enzyme). The data obtained are compared with literary data on other cyclic choline esterase substrates; they are discussed from the viewpoint of unproductive binding hypothesis and on the basis of the structure of active centres of acetyl- and butyrylcholine esterases.

Acetates↗

PubMed1995

Hormone replacement therapy and atherosclerosis.

Atherosclerotic changes associated with long-term hormone replacement therapy (HRT) were evaluated in 20 postmenopausal women (mean age, 62.8 +/- 6.1 years). The duration of hormone therapy was 10.1 +/- 3.4 (SD) years. For 9 women the HRT was sequential estradiol valerate plus levonorgestrel, for 6 women estradiol valerate plus medroxyprogesterone acetate and for 5 women estradiol valerate alone. Examinations consisted of histologic and biochemical studies of the uterine artery and ultrasonographic examinations of carotid arteries, aorta and iliac arteries. The findings were compared with those in 20 postmenopausal women of similar age and with similar body mass indexes who had never received HRT. Additionally, the same examinations were performed on 10 premenopausal women (48.3 +/- 4.6 years). The uterine artery was histologically normal in all the premenopausal women studied. Among the postmenopausal women without HRT, a histologically normal uterine artery was found in 5% and in women on HRT in 55% of cases (P < .01). In medicolegal autopsies, atherosclerosis in the uterine artery correlated significantly with atherosclerosis in the coronary artery and aorta. The free cholesterol content of the intima media in premenopausal women was lower than in postmenopausal women without HRT. The percentage of linoleic acid in the intima was significantly lower and that of docosapentaenoic acid significantly higher in premenopausal women and in postmenopausal women on HRT than in postmenopausal women without HRT. In the ultrasonographic examination atherosclerosis in the carotid artery was less common in premenopausal women and in women on HRT than in postmenopausal women without HRT. In this material, histologic, biochemical and radiologic studies showed that HRT may be protective against atherosclerosis.

Adult↗

PubMed1982

Inhibitory effect of short-chain aliphatic acids on deoxythymidine incorporation into DNA in mitogen-stimulated and leukemic lymphocytes.

The effect of short-chain aliphatic acids on [3H]deoxythymidine incorporation into DNA was studied in human mitogen-stimulated lymphocytes. Butyric acid at 1-2 mM level was strongly inhibitory; however, its hydroxy or amino derivatives were ineffective. Valeric and propionic acids were less inhibitory. Formic, acetic, and hexanoic acids did not have any inhibitory effect. The effect of butyrate persisted in washed lymphocytes for 24-48 hr depending on the concentration used and the time of its addition into the incubation medium. The inhibitory effects of butyrate, valerate, and propionate on deoxythymidine and amino acid incorporation into DNA and protein were also found in human leukocytes in myelocytic and lymphocytic leukemias.

Acetates↗

PubMed1993

Facilitated transport of two model steroids by esters and amides of clofibric acid.

A series of novel dermal penetration enhancers, esters and amides of clofibric acid, was synthesized. The permeation parameters and skin retention of two steroids (hydrocortisone-21-acetate and betamethasone-17-valerate) in propylene glycol were studied with athymic nude mouse skin by in vitro diffusion cell techniques in the presence of the novel enhancer compounds. Isopropyl myristate, dimethyl lauramide, and 1-dodecylazacycloheptan-2-one (laurocapram, Azone) were used as control enhancers. The most satisfactory enhancement of both the ester and amide series was observed with clofibric acid octyl amide; coadministration increased skin retention of hydrocortisone acetate after 24 h by 3.5-fold and that of betamethasone valerate by 2.9-fold. Diffusion cell receptor concentrations increased 51.6- and 10.3-fold, respectively, during the same time period. However, the enhancer compound in this case was applied to the skin 1 h prior to each of the steroids. The amide analogues were more effective than the equivalent ester compounds of the same carbon chain length. The best enhancer compounds (2c, 3d, 3e, and 3f) were nonirritating to athymic mouse skin in vivo.

Animals↗

PubMed1993

Percutaneous absorption: a single-layer model.

In vitro percutaneous permeation of betamethasone 17-valerate through excised human skin was studied. Pressure-sensitive silicone adhesive containing betamethasone 17-valerate in suspension was used as a vehicle. Steady-state flux through the split-thickness skin was similar to that through the isolated epidermis. However, the lag-time and half-life after removal of the vehicle were longer for the split-thickness skin than from epidermis. At steady state, 37% of the drug in the split-thickness skin was partitioned in dermis. When the kinetic parameters of a simple single-layer model are defined to specify the permeability coefficient and the drug amount in skin at steady state, this model can predict the longer half-life observed for the split-thickness skin sample compared with that for epidermis. The difference between the observed and theoretical values of the half-life after removal of the vehicle was within 23%. On the other hand, the lag-time had a large variation and the simple diffusion model failed to be predictive. A single-layer model described by two or three kinetic parameters may be able to describe percutaneous permeation kinetics even when the processes after the compound permeation through stratum corneum are not negligible. However, it is stressed that none of the kinetic parameters inherent in this simple model directly represents one of the single physicochemical parameters, such as diffusion and partition coefficients and path length of each skin layer.

Betamethasone Valerate↗

PubMed1976

A controlled trial of inhaled corticosteroids in patients receiving Prednisone tablets for asthma.

The theraprutic efficacy of inhaled beclomethasone dipropionate and inhaled betamethasone valerate in chronic asthma has been studied in 14 treatment centres in 158 patients who had previously been taking prednisone tablets regularly. Doses of 400 mug daily of beclomethasone dipropionate and a dose of 800 mug daily of betamethasone valerate allowed approximately 80% of patients to discontinue prednisone initially and 60% to remain off daily prednisone for 24 weeks. A mean reduction in daily prednisone dose of 8 mg was achieved by patients inhaling corticosteroids whilst placebo inhaler permitted a 5 mg reduction. The three inhaled corticosteroid preparations were equally effective in facilitating prednisone reduction and provided equally good control of asthma, alone or as an ancillary to prednisone. The higher dose of beclomethasone dipropionate was superior to the lower in permitting more patients to remain off daily prednisone for the period of the trial. Although 82% of patients recovered a normal adrenal response to tetracosactrin 24 weeks after prednisone was discontinued and inhaled corticosteroids subsituted, 18% still showed some suppression of adrenal function. There was no significant difference between the treatment groups in this.

Aerosols↗

PubMed1995

Separation of two forms of neuropathy target esterase in the soluble fraction of the hen sciatic nerve.

Neuropathy target esterase (NTE) activity is operatively defined in this paper as the phenyl valerate esterase activity resistant to 40 microM paraoxon but sensitive to 250 microM mipafox. Molecular exclusion column chromatography with Sephacryl S-300 of the soluble (S) fraction from chick sciatic nerve demonstrated two NTE activity peaks. The first eluted with the front, thus indicating a mol. wt. of over 700 kDa (peak Vo), while the second peak eluted with kd = 0.36, suggesting a mol. wt. of about 100 kDa. The curve of total phenyl valerate (PVase) activity inhibition with paraoxon (0.19-200 microM) shows that at a concentration of 40 microM the esterases highly sensitive to paraoxon are inhibited in the Vo and 100-kDa peaks. The NTE activity in these two peaks in turn represented 31% and 44% of the 40 microM paraoxon resistant activity, respectively. The mipafox inhibition curves (1.0-250 microM) revealed different sensitivities to mipafox, with I50 values (t = 30 min) of approximately 1.47 and 63 microM, for Vo and 100-kDa peaks respectively. Mipafox sensitivity of the Vo and 100-kDa peaks correlates with the two components, that had been deduced from the kinetic properties of the S-fraction.

Animals↗

PubMed1996

Bovine chromaffin cells in culture show carboxylesterase activities sensitive to organophosphorus compounds.

Carboxylesterase activities are widely distributed in a great variety of tissues; however, the biological function of these enzymes remains unclear. Some organophosphorus compounds induce a neurodegenarative syndrome related to the covalent modification of a carboxylesterase known as neuropathy target esterase. We investigated the expression of neuropathy target esterase and related carboxylesterase in bovine chromaffin cells with the aim of developing a potential in vitro model for studying the cellular function of carboxylesterase enzymes and toxic effects of organophosphorus compounds. Total phenyl valerate esterase exhibited an activity of 1.27 +/- 0.19 mU/10(5) cells (SD, n = 15). From the phenyl valerate esterase paraoxon and mipafox inhibition curves the following activities have been determined: B-activity (resistant to 40 microM paraoxon), 1.05 +/- 0.08 mU/10(5) cells (n = 8); C-activity (resistant to 40 microM paraoxon plus 250 microM mipafox), 0.12 +/- 0.05 mU/10(5) cells (n = 8); and neuropathy target esterase, calculated by the difference between B- and C-activities, 0.93 +/- 0.08 mU/10(5) cells (n = 8). All of these activities increased linearly with the number of cells and time of incubation with the substrate. Most of the phenol product of the reaction was released and detected in the extracellular medium. None of the components of the reaction were shown to affect cell viability when assessed by trypan blue exclusion. The study shows that bovine chromaffin cells possess carboxylesterase activities and respond to inhibition by paraoxon and mipafox, thus facilitating the discrimination of neuropathy target esterase. In conclusion, bovine chromaffin cells are appropriate as an in vitro cell model for studying toxic effects of organophosphorus compounds.

Animals↗

PubMed1967

The gas-liquid chromatography of carboxylic acid esters of the urinary 11-deoxy-17-oxo steroids. Determination as n-butyrates.

1. The gas-liquid-chromatographic separations of the acetate, propionate, n-butyrate, isobutyrate and n-valerate esters of androsterone, aetiocholanolone and dehydroepiandrosterone were studied on a 1% neopentyl glycol sebacate column. The n-butyrate, isobutyrate and n-valerate esters were well resolved. 2. The three steroids derived from hydrolysed urinary 17-oxo steroid conjugate extracts were analysed by gas-liquid chromatography after conversion into their n-butyrate esters. The results were compared with independent determinations involving chromatography on alumina.

17-Ketosteroids↗

PubMed1974

Properties and substrate specificity of some reactions catalysed by a short-chain fatty acyl-coenzyme A synthetase from seeds of Pinus radiata.

1. Crude extracts of seeds of Pinus radiata catalysed acetate-, propionate-, n-butyrate- and n-valerate-dependent PP(i)-ATP exchange in the presence of MgCl(2), which was apparently due to a single enzyme. Propionate was the preferred substrate. Crude extracts did not catalyse medium-chain or long-chain fatty acid-dependent exchange. 2. Ungerminated dry seeds contained short-chain fatty acyl-CoA synthetase activity. The activity per seed was approximately constant for 11 days after imbibition and then declined. The enzyme was located only in the female gametophyte tissue. 3. The synthetase was purified 70-fold. 4. Some properties of the enzyme were studied by [(32)P]PP(i)-ATP exchange. K(m) values for acetate, propionate, n-butyrate and n-valerate were 4.7, 0.21, 0.33 and 2.1mm respectively. Competition experiments between acetate and propionate demonstrated that only one enzyme was involved and confirmed that the affinity of the enzyme for propionate was greater than that for acetate. CoA inhibited fatty acid-dependent PP(i)-ATP exchange. The enzyme catalysed fatty acid-dependent [(32)P]PP(i)-dATP exchange. 5. The enzyme also catalysed the fatty acyl-AMP-dependent synthesis of [(32)P]ATP from [(32)P]PP(i). Apparent K(m) (acetyl-AMP) and apparent K(m) (propionyl-AMP) were 57mum and 7.5mum respectively. The reaction was inhibited by AMP and CoA. 6. Purified enzyme catalysed the synthesis of acetyl-CoA and propionyl-CoA. Apparent K(m) (acetate) and apparent K(m) (propionate) were 16mm and 7.5mm respectively. The rate of formation of acetyl-CoA was enhanced by pyrophosphatase. 7. It was concluded that fatty acyl adenylates are intermediates in the formation of the corresponding fatty acyl-CoA.

Acetates↗