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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Drosophila yolk proteins consist of a set of related proteins of 50,000 Mr. They are derived from slightly larger precursors by cleavage of a signal peptide. In this respect, they differ from the yolk proteins of other insects which are proteolytic fragments of precursors of 200,000 Mr or larger, termed vitellogenins and probably homologous to the vitellogenins of other egg-laying species. We report here a comparative amino acid analysis demonstrating that the Drosophila yolk proteins are non-homologous to the vitellogenin group of yolk proteins, but surprisingly are related to the triacylglycerol lipase family.
J Mol Biol 1988 Aug 05
PMID:Homology of Drosophila yolk proteins and the triacylglycerol lipase family. 313 89

The effect of halothane on isoproterenol-stimulated lipolysis was determined in isolated rat epididymal fat cells. The maximal lipolytic response (Emax) activated by isoproterenol was 350 +/- 61 nmol of glycerol/10(5) cells/hr with an EC50 of 5.1 X 10(-9) M. When the adipocytes were simultaneously bubbled with 2.5% halothane, the Emax decreased to 158 +/- 43 nmol of glycerol/10(5) cells/hr and the dose response curve for isoproterenol was shifted to the right (EC50 3.5 X 10(-8) M, p less than 0.05). When lipolysis was maximally stimulated with (-)-isoproterenol (10(-6)M), the inhibitory effect of halothane was found to be both dose dependent (IC50 approximately 2.5%, v/v) and reversible following washout. Neither the nonhydrolyzable cAMP analog, 8-(4-chlorophenylthio) adenosine 3',5'-cyclic monophosphate (2 X 10(-3)M), nor forskolin (10(-6) M) was able to normalize lipolysis in the presence of halothane. The activation of cAMP-dependent protein kinase (EC 2.7.1.37) activity by isoproterenol was not different in halothane-exposed cells when compared to unexposed cells. When control adipocytes were exposed to isoproterenol (10(-6) M), there was a 2.5-fold increase in the activity of hormone-sensitive lipase (EC 3.1.1.3) from 0.64 +/- 0.13 to 1.53 +/- 0.32 pkat (pmol/sec) per mg (p less than 0.005, n = 10). However, in the presence of halothane (2.5%, v/v) isoproterenol stimulation of hormone-sensitive lipase was attenuated by 50% to values of 1.06 +/- 0.23 pkat/mg (p less than 0.01, n = 10). Halothane had no direct inhibitory effect on hormone-sensitive lipase since this enzyme's activity was unaffected when homogenates of isoproterenol-stimulated control cells were incubated with halothane. These studies suggest that halothane impairs the activation of hormone-sensitive lipase by cAMP-dependent protein kinase and in this manner inhibits beta-adrenergic-stimulated lipolysis.
Mol Pharmacol 1988 Mar
PMID:Mechanism of halothane-induced inhibition of isoproterenol-stimulated lipolysis in isolated rat adipocytes. 335 97

The impact of lowering the ovarian L(iver)-type lipase activity on cholesterol homeostasis in the ovaries was studied in superovulated rats. L-type lipase activity increased rapidly after injection with chorionic gonadotrophin (HCG) (day 0), its activity remained high between days 3 and 8. During this period plasma progesterone and 20 alpha-hydroxyprogesterone were raised. The ovarian content of unesterified cholesterol remained constant during this period while cholesterol esters increased. Lowering of the L-type lipase activity by in vivo treatment with anti-liver lipase (ALLA) during 4-5 h did not affect plasma hormones or ovarian cholesterol contents. However, de novo cholesterol synthesis in the ovaries was significantly increased by about 40%. After pretreatment of the rats with aminogluthetimide, ALLA administration led to a 250% increase in de novo cholesterol synthesis in the unesterified cholesterol fraction, but was without effect on plasma hormones and on the ovarian cholesterol content. Administration of the cholesterol synthesis inhibitor Simvastatin led to a 25% lowering in ovarian cholesterol synthesis without effect on plasma hormones or ovarian cholesterol content. Additional administration of ALLA affected only the plasma progesterone (-30%). These results indicate that L-type lipase is involved in ovarian cholesterol homeostasis.
Mol Cell Endocrinol 1988 May
PMID:L-type lipase activity in ovaries of superovulated rats. Relation to cholesterol homeostasis. 339 58

The lipase activity of the adult rat heart consists of at least two components; a lipoprotein lipase and a "hormone-sensitive" or triglyceride lipase. The control of the triglyceride lipase by intermediates of lipid metabolism was studied in rat heart homogenates. Perfusion of hearts with fatty acids, glucose or no exogenous substrate did not alter lipase activity. Bovine serum albumin (BSA) stimulated the in vitro lipase activity whereas palmityl-coenzyme A (CoA) was a potent inhibitor. Other fatty acid intermediates such as acetyl-CoA, acetyl-carnitine, palmityl-carnitine and palmitate had little or no effect. Long-chain acyl CoA may be an important intermediate for matching triglyceride hydrolysis with the supply of extracellular fatty acids and the rates of fatty acid oxidation.
J Mol Cell Cardiol 1988 Mar
PMID:Inhibition of myocardial lipase by palmityl CoA. 341 15

The conditions for an in vitro assay of liver-type lipase, i.e. an enzyme resembling the lipase releasable from the liver by heparin (liver lipase), in rat ovaries were established. The liver-type lipase activity in the ovaries was almost completely (greater than 95%) located in the corpora lutea and its activity ranged from 0.44 to 0.77 mU per corpus luteum of (pseudo)pregnant rats. Preovulatory ovarian follicles contained very low lipase activity. During the estrous cycle the pattern of lipase activity was similar to that of serum progesterone levels (maximal at diestrus 1 and minimal at diestrus 2). In the individual rats liver-type lipase activity in the ovaries was strongly correlated with serum progesterone and 20 alpha-hydroxyprogesterone. The activity of liver-type lipase also varied during lactation. It was relatively low at an early stage (2-3 days) but increased during later stages of lactation. The serum progesterone level was relatively low in rats lactating for 2-3 or 22-24 days. During the intervening time, its concentrations was elevated. Since serum 20 alpha-hydroxyprogesterone levels varied inversely to progesterone, the total amount of progestagens in blood during lactation remained constant. The cholesterol content of the corpora lutea of the lactating rats was initially high and decreased during the lactation.
Mol Cell Endocrinol 1985 Oct
PMID:Localization of liver-type lipase in rat ovaries and its activity during the estrous cycle and lactation. 404 19

Glycerol 3-phosphate acyltransferase (GPAT) activity and triglyceride lipase (TGL) activity were measured in homogenates from hearts perfused with adrenergic agonists and antagonists. Perfusion with adrenalin or the beta-agonist isoprenaline produced an increase in TGL activity and a fall in GPAT activity. These changes could be imitated by incubation of heart homogenates with cAMP-dependent protein kinase. The alpha 2-agonist clondine produced the opposite effect, thus it increased GPAT activity and decreased TGL activity. Methoxamine, an alpha 1-agonist, had no effect on TGL activity but reduced GPAT activity. Continuous perfusion of the beta-antagonist atenolol reduced TGL activity to half that found in controls but also reduced GPAT activity. No change was seen on continuous perfusion of alpha 1- or alpha 2-antagonists. Changes in GPAT activity were localized mainly in the microsomal enzyme. These changes are consistent with both enzymes being regulated via a cyclic-AMP dependent protein kinase system and via alpha-adrenergic mechanisms.
J Mol Cell Cardiol 1985 Aug
PMID:The effect of adrenergic agents on the activities of glycerol 3-phosphate acyltransferase and triglyceride lipase in the isolated perfused rat heart. 404 45

In brown adipose tissue of the rat, chemically or surgically induced hypothyroidism caused the following effects. A large decrease of the magnitude of the metabolic response to electrical nerve stimulation. The deactivation half-time of the response was reduced to 70% of the control value, with no change in catechol O-methyltransferase activity. Pre-incubation of tissues with norepinephrine, 10(-5) M, increased the response to subsequent nerve stimulation almost to that of the controls. The catecholamine analogue dose-response curves were shifted to the right. The shift was very pronounced for isoproterenol (K50 426 nM versus 2 nM), somewhat less marked for norepinephrine (7373 nM versus 194) and very slight for phenylephrine (2803 nM versus 1649); there was almost no change in Emax values. An increase of octanoate oxidative capacity. A decrease of the capacity of the stereoselective binding of (-)-[3H]dihydroalprenolol of the high-affinity (Kd 2.0 nM) sites to a fourth of the control value and an increase by a factor of 2.9 of the Kd of the low-affinity binding sites. This decrease of binding to the beta-receptors was not sufficient quantitatively to explain the decrease in the metabolic response, suggesting the existence of an additional defective reaction which could occur between the binding to the beta-receptors and the activation of the triglyceride lipase. These results show that the sharp decrease of the metabolic response of brown adipose tissue to nerve stimulation has multiple causes. The findings are discussed in the context of the drastic decrease of cold resistance in hypothyroid rats.
Mol Cell Endocrinol 1982 Feb
PMID:Impaired metabolic response to nerve stimulation in brown adipose tissue of hypothyroid rats. 627 52

Forskolin increased cyclic AMP accumulation in isolated adipocytes and markedly potentiated the elevation of cyclic AMP due to isoproterenol. In adipocyte membranes, forskolin stimulated adenylate cyclase activity at concentrations of 0.1 microM or greater. Forskolin did not affect the EC50 for activation of adenylate cyclase but did increase the maximal effect of isoproterenol. Neither the soluble nor particulate low-Km cyclic AMP phosphodiesterase activity was affected by forskolin. Low concentrations of forskolin (0.1-1.0 microM), which significantly elevated cyclic AMP levels, did not increase lipolysis, whereas similar increases in cyclic AMP levels due to isoproterenol elevated lipolysis. Forskolin did not inhibit the activation of triacylglycerol lipase by cyclic AMP-dependent protein kinase or the subsequent hydrolysis of triacylglycerol. Higher concentrations of forskolin (10-100 microM) did increase lipolysis. Both the increased cyclic AMP production and lipolysis due to forskolin were inhibited by the antilipolytic agents insulin and N6-(phenylisopropyl)adenosine. Hypothyroidism reduced the ability of forskolin to stimulate cyclic AMP production and lipolysis. These results indicate that forskolin increases cyclic AMP production in adipocytes through an activation of adenylate cyclase. Lipolysis is activated by forskolin but at higher concentrations of total cyclic AMP than for catecholamines.
Mol Pharmacol 1982 Jul
PMID:Forskolin as an activator of cyclic AMP accumulation and lipolysis in rat adipocytes. 628 66

The activities of hormone-sensitive cholesterol esterase and hormone-sensitive triacylglycerol lipase from rat adrenal glands were enhanced about 2-fold by means of ether stress and showed parallel elution profiles on a Sepharose CL-6B column. Both enzymatic activities were inhibited to a similar extent by DFP after separation from hormone-insensitive lipase on heparin-Sepharose. Fractions from the gel filtration column containing the two hormone-sensitive enzymes showed incorporation of tritium-labelled DFP into only one polypeptide of Mr 84 000. From these results we conclude that both hormone-sensitive activities reside on one polypeptide of Mr 84 000, thus providing further support to the concept that the different hormone-sensitive acylester hydrolase activities in steroid-secreting tissues as well as in adipose tissue are performed by the same bifunctional enzyme. In addition to the hormone-sensitive enzyme, rat adrenals contained high amounts of neutral triacylglycerol lipase activity which was not affected by stress. The latter enzyme was resistant to high salt concentrations, was less susceptible to inhibition by DFP, but could be inhibited completely by the addition of antibodies raised against rat liver lipase, thus most probably representing the adrenal liver lipase-like triacylglycerol lipase.
Mol Cell Endocrinol 1984 May
PMID:Regulation of steroidogenesis in rat adrenal gland: identification of the bifunctional, hormone-sensitive cholesterol esterase--triacylglycerol lipase enzyme protein and its discrimination from hormone-insensitive lipases. 673 27

African swine fever virus polypeptides with molecular weight of 120, 78, 69, 59, 56, 45, 39, 28, 26, 24, 16, and 14 kD are the major proteins in the purified virions, as shown by electrophoresis and immunoblotting. A mixture of proteases and pancreatic lipase hydrolyzed the polypeptides of 120 and 78 kD in viral preparations at low concentrations of enzymes, polypeptides of 69, 56, 45, 39, 28, and 14 kD disappeared after treatment with this mixture at medium concentrations, and 26 kD polypeptide was eliminated at a high concentration of the enzymes. The 21 kD polypeptide which did not react with the specific antiviral serum in immunoblotting was not hydrolyzed by proteases contaminating lipase. Treatment with triton X-100 and ether boosted the activity of DNA-dependent RNA-polymerase, whereas treatment with ether followed by resedimentation markedly decreased polymerase activity in the resultant sediment. Treatment with diethyl ether did not influence the activity of virus-associated ATPase, which was partially resistant to denaturating organic solvents acetone and chloroform-methanol mixture. Our findings and published data permitted us to propose a schematic arrangement of viral polypeptides and enzymes in the virion structure.
Mol Gen Mikrobiol Virusol
PMID:[Localizing the major peptides of African swine fever virus and virus-associated enzymes in the virion structure]. 747 38


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