scholarly journals Cloning of cDNA to rat mammary-gland fatty acid synthase mRNA. Evidence for the expression of two mRNA species during lactation

1988 ◽  
Vol 249 (2) ◽  
pp. 603-607 ◽  
Author(s):  
M Braddock ◽  
D G Hardie
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Cdna Library ◽  
Fatty Acid Synthase ◽  
Expression Vector ◽  
Base Pairs ◽  
Coding Sequences ◽  
Mrna Species ◽  
Rat Mammary Gland ◽  
Lac Z

A cDNA library was constructed in the expression vector lambda gt11, by synthesizing cDNA from size-selected poly(A) RNA from lactating rat mammary gland, using random hexanucleotide primers. Using this library we identified two recombinants which, on addition of a lac z inducer, produced proteins recognized by affinity-purified anti-fatty-acid synthase antibody, and which, therefore, contained fatty acid synthase coding sequences. The inserts were subcloned, were shown to be between 500 and 600 base pairs in size, and to cross-hybridize. The cloned DNA was then used in Northern hybridizations with mRNA isolated at various stages throughout lactation. Two mRNA species were identified of approx. 9.7 and 10.4 kilobases, which increased and decreased in parallel during lactation, reaching a peak at 12-13 days. Both mRNA species disappeared rapidly if the pups were removed prematurely. This study provides evidence that, during hormonal induction in lactation, regulation of the level of fatty acid synthase protein can be accounted for by variation in the level of mRNA.

scholarly journals Rat mammary-gland fatty acid synthase. A simple purification procedure and stoicheiometry of CoA ester binding

1982 ◽  
Vol 203 (1) ◽  
pp. 45-50 ◽  
Author(s):  
P M Ahmad ◽  
D S Feltman ◽  
F Ahmad
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Simple Procedure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Performic Acid ◽  
Mammary Tissue ◽  
Rat Mammary Gland

A simple procedure was devised which allows purification of rat lactating-mammary-gland fatty acid synthase to a high degree of purity, with recoveries of activity exceeding 50%. Over 50 mg of enzyme was isolated from 60 g of mammary tissue. The specific activity of the purified enzyme was about 2.5 mumol of NADPH oxidized/min per mg of protein at 37 degrees. The enzyme appeared homogeneous by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and by immunodiffusion analysis. Each mol (Mr 480 000) of the enzyme bound 3 mol of acetyl and 3-4 mol of malonyl groups when the binding experiments were performed at 0 degrees for 30 s. The presence of NADPH did not influence the binding stoicheiometry for these acyl-CoA derivatives. Approx. 2 mol of taurine was found per mol of the performic acid-oxidized enzyme, suggesting that there were 2 mol of 4′-phosphopantetheine in the native enzyme. Rat mammary-gland fatty acid synthase required free CoA for activity.

scholarly journals Studies on acetyl-CoA carboxylase and fatty acid synthase from rat mammary gland and mammary tumours

1982 ◽  
Vol 208 (2) ◽  
pp. 443-452 ◽  
Author(s):  
P M Ahmad ◽  
D S Feltman ◽  
F Ahmad
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Mammary Tissue ◽  
Acetyl Coa Carboxylase ◽  
Lipogenic Enzymes ◽  
Acetyl Coa ◽  
Rat Mammary Gland ◽  
Mammary Gland Differentiation ◽  
Mammary Adenocarcinomas

The activities of two lipogenic enzymes, acetyl-CoA carboxylase and fatty acid synthase, were determined in two transplantable mammary adenocarcinomas (13762 and R3230AC) carried by non-pregnant, pregnant and lactating rats, and in mammary tissue of control animals (non-tumour-carrying) of comparable physiological states. During mammary-gland differentiation of control or tumour-carrying animals, the activities of acetyl-CoA carboxylase and fatty acid synthase in the lactating gland increased by about 40-50-fold over the values found in non-pregnant animals. On the other hand, in tumours carried by lactating dams there were only modest increases (1.5-2-fold) in acetyl-CoA carboxylase and fatty acid synthase compared with the neoplasms carried by non-pregnant animals. On the basis of the Km values for different substrates and immunodiffusion and immunotitration data, the fatty acid synthase of neoplastic tissues appeared to be indistinguishable from the control mammary-gland enzyme. However, a comparison of the immunotitration and immunodiffusion experiments indicated that the mammary-gland acetyl-CoA carboxylase might differ from the enzyme present in mammary neoplasms.

scholarly journals Rat mammary gland fatty acid synthase: localization of the constituent domains and two functional polyadenylation/termination signals in the cDNA

1989 ◽  
Vol 17 (2) ◽  
pp. 567-586 ◽  
Author(s):  
Michael Schweizer ◽  
Kenji Takabayashi ◽  
Thomas Laux ◽  
Karl-Friedrich Beck ◽  
Rosemarie Schreglmann
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Rat Mammary Gland

Active site directed inactivation of rat mammary gland fatty acid synthase by 3-chloropropionyl coenzyme A

Biochemistry ◽  
1986 ◽  
Vol 25 (2) ◽  
pp. 468-473 ◽  
Author(s):  
Henry M. Miziorko ◽  
Christine E. Behnke ◽  
Patricia M. Ahmad ◽  
Fazal Ahmad
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Active Site ◽  
Fatty Acid Synthase ◽  
Coenzyme A ◽  
Rat Mammary Gland

scholarly journals Irreversible inhibition of fatty acid synthase from rat mammary gland with S-(4-bromo-2,3-dioxobutyl)-CoA. Effect on the partial reactions, protection by substrates and stoichiometry studies

1982 ◽  
Vol 207 (2) ◽  
pp. 291-296 ◽  
Author(s):  
P R Clements ◽  
R E Barden ◽  
P M Ahmad ◽  
M B Chisner ◽  
F Ahmad
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Bimolecular Reaction ◽  
Alkylation Reaction ◽  
Thiol Groups ◽  
Partial Reaction ◽  
Nitrobenzoic Acid ◽  
Irreversible Inhibition ◽  
Rat Mammary Gland

Fatty acid synthase from lactating rat mammary gland is rapidly and irreversibly inhibited by S-(4-bromo-2,3-dioxobutyl)-CoA. Of the seven partial reactions catalysed by the enzyme, the inhibition of the overall catalytic activity is closely paralleled only by inhibition of the beta-oxoacyl synthase (condensing) partial reaction. Three partial reactions. Beta-oxoacyl reductase, beta-hydroxyacyl dehydratase and enoyl reductase, are inhibited to a modest degree. The three partial reactions known to involve an acyl-CoA/CoA-binding site, acetyl acyltransferase, malonyl acyltransferase and palmitoyl thioesterase, are not inhibited by S-(4-bromo-2,3-dioxobutyl)-CoA. The modification process does not cause the enzyme to dissociate into catalytically incompetent monomers. Stoichiometric studies suggest that approx. 6 mol of reagent are incorporated per mol of totally inhibited enzyme (dimer). The formation of acylated enzyme from either acetyl-CoA or malonyl-CoA protects the enzyme equally well against S-(4-bromo-2,3-dioxobutyl)-CoA. Also, pretreatment of the enzyme with 5,5′-dithiobis-(2-nitrobenzoic acid), a thiol-specific reagent reported to block essential thiol groups in the condensing partial reaction, protects against inhibition by the reagent. On the other hand, the presence of up to 770 microM-S-acetonyl-CoA or dethio-CoA does not protect the enzyme from irreversible inhibition. Together, the results suggest that the primary inhibitory process is a bimolecular reaction resulting in alkylation of essential thiol groups in the condensing partial reaction: this process does not require the obligatory formation of a Michaelis-Menten complex of enzyme and reagent before the alkylation reaction.

scholarly journals Regulation of lipogenic capacity in lactating rats

1982 ◽  
Vol 208 (3) ◽  
pp. 611-618 ◽  
Author(s):  
M R Grigor ◽  
A Geursen ◽  
M J Sneyd ◽  
S M Warren
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Malic Enzyme ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Mammary Glands ◽  
Lipogenic Enzymes ◽  
Pregnancy And Lactation ◽  
Specific Activities

1. The rate of mammary-gland lipogenesis measured in vivo from 3H2O was suppressed after decreasing the milk demand by decreasing the number of pups from ten to two or three, as well as by giving diets containing lipid [Grigor & Warren (1980) Biochem. J. 188, 61-65]. 2. The specific activities of the lipogenic enzymes fatty acid synthase, glucose 6-phosphate dehydrogenase and ‘malic’ enzyme increased between 6- and 10-fold in the mammary gland and between 2- and 3-fold in the livers during the first 10 days of lactation. The increases in specific activity coupled with the doubling of liver mass which occurred during pregnancy and lactation resulted in considerable differences in total liver activities when compared with virgin animals. 3. Although consumption of a diet containing 20% peanut oil suppressed the activities of the three lipogenic enzymes in the livers, only the ‘malic’ enzyme was affected in the mammary glands. 4. In contrast, decreased milk demand did not affect the specific activities of any of the liver enzymes, whereas it resulted in suppression of all three lipogenic enzymes of the mammary glands. There was no effect on either the cytoplasmic malate dehydrogenase or the lactate dehydrogenase of the mammary gland. 5. In all the experiments performed, the activity of the fatty acid synthase correlated with the amount of material precipitated by the rabbit antibody raised against rat fatty acid synthase.

scholarly journals Protein degradation during terminal cytodifferentiation. Studies on mammary gland in organ culture

1980 ◽  
Vol 192 (1) ◽  
pp. 311-320 ◽  
Author(s):  
C J Wilde ◽  
N Paskin ◽  
J Saxton ◽  
R J Mayer
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Protein Degradation ◽  
Degradation Rate ◽  
Fatty Acid Synthase ◽  
Average Rate ◽  
Cytosol Fraction ◽  
Isotope Method ◽  
Degradation Rates ◽  
Double Isotope

1. In mammary gland explants subjected to experimental manipulation, average rates (during 24 h periods) of degradation of fatty acid synthase, casein and cytosol-fraction proteins were measured by a double-isotope method. Rates of degradation of fatty acid synthase were also computed from measurements of changing enzyme amount and rate of synthesis. 2. During the period of most rapid enzyme accumulation there is a transient decrease in the computed rate of degradation of fatty acid synthase. Removal of hormones produces a rapid increase in the computed rate of degradation of the enzyme. 3. The average rate of degradation of fatty acid synthase measured by the double-isotope method is low in the presence of hormones, and increases on hormone removal. This increase in degradation rate is inhibited by adrenaline and further blocked by insulin. NH4Cl (10 mM) also partially inhibits the increase in protein degradation on hormone removal. 4. The pattern of changes in the average rate of degradation of cytosol-fraction proteins is similar to that for fatty acid synthase alone. There is no relationship between subunit molecular weight and rate of degradation under all experimental conditions. 5. Isotope ratios for resolved cytosol protein mixtures are transformed logarithmically to make the standard deviations an estimate of heterogeneity of degradation rates. By this analysis, in some conditions there appears to be significant measureable heterogeneity of degradation rates. 6. Little degradation of casein is measured in the presence of hormones, but a marked increase in the rate of degradation can be measured when hormones are removed. Whereas at 24-48h NH4Cl (10 mM) has little effect on this enhanced rate of degradation, at 48-72h it causes a large decrease in degradation rate. 7. Results are discussed in terms of a two-component degradation system in mammary gland explants.

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