Intramitochondrial localization of delta-aminolaevulate synthetase and ferrochelatase in rat liver.
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ABSTRACT:
SUBMITTER: McKay R
PROVIDER: S-EPMC1184917 | biostudies-other | 1969 Sep
REPOSITORIES: biostudies-other
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Project description:1. delta-Aminolaevulate synthetase was detected in liver and kidney mitochondria prepared from normal rats. 2. The administration of allylisopropylacetamide induced an increase in delta-aminolaevulate synthetase in both liver and kidney mitochondria and the enzyme also appeared in the cytosol fraction of both tissues. Comparison with the distribution of glutamate dehydrogenase indicated that this soluble kidney delta-aminolaevulate synthetase was truly of cytosol origin and did not arise from disrupted mitochondria. The kidney cytosol enzyme was inhibited by 50% by 50mum-protohaem. 3. delta-Aminolaevulate synthetase could not be detected in mitochondria or cytosol from heart or brain from normal or porphyric rats. 4. The administration of allylisopropylacetamide caused little or no increase in ferrochelatase or cytochrome content of liver, kidney, heart or brain mitochondria.
| S-EPMC1177233 | biostudies-other
Project description:1. delta-Aminolaevulate synthetase from Rhodopseudomonas spheroides grown semi-anaerobically undergoes a spontaneous activation during the first hour after the disruption of cells when homogenates are stored at 4 degrees . 2. After cultures of R. spheroides growing semi-anaerobically are oxygenated no activation of delta-aminolaevulate synthetase occurs in cell extracts. Cessation of activation in extracts is almost complete 10min. after oxygenation of cells has begun. 3. A heat-stable fraction of low molecular weight from semi-anaerobic cells reactivates delta-aminolaevulate synthetase in extracts of oxygenated cells and appears to contain a compound responsible for the spontaneous activation. 4. A heat-stable fraction of low molecular weight from oxygenated cells inhibits the spontaneous activation in extracts of semi-anaerobic cells. 5. The effect of oxygen on the rate of bacteriochlorophyll synthesis in R. spheroides may be mediated through alterations in the concentrations of a low-molecular-weight activator and inhibitor of delta-aminolaevulate synthetase.
| S-EPMC1187556 | biostudies-other
Project description:1. The spontaneous activation of delta-aminolaevulate synthetase in extracts from Rhodopseudomonas spheroides grown semi-anaerobically in the light requires oxygen and does not take place anaerobically in the dark. 2. Activation is completely prevented by azide or cyanide and is partially inhibited by chlorpromazine. These compounds inhibit markedly the succinoxidase activity of extracts. 3. NADH delays activation, but when it has been oxidized by the extract activation begins at the normal rate and complete activation occurs. By contrast both the rate and the extent of activation are markedly decreased by even small amounts of carboxylic acids. 4. The inhibitory effects of succinate and citrate on activation can be prevented by malonate and fluorocitrate respectively. 5. These results suggest that for activation to occur some endogenous compound has to be oxidized via the electron transport chain. 6. Activation occurs under anaerobic conditions in the light, probably by photo-oxidation.
| S-EPMC1178966 | biostudies-other
Project description:A reciprocal relationship exists between the cytochrome P-450 content and delta-aminolaevulinate synthetase activity in adult rats. In young rats the basal delta-aminolaevulinate synthetase activity is higher and the cytochrome P-450 content is lower compared with the adult rat liver. Administration of allylisopropylacetamide neither induces the enzyme nor causes degradation of cytochrome P-450 in the young rat liver, unlike adult rat liver. Allylisopropylacetamide fails to induce delta-aminolaevulinate synthetase in adrenalectomized-ovariectomized animals or intact animals pretreated with successive doses of the drug, in the absence of cortisol. The cortisol-mediated induction of the enzyme is sensitive to actinomycin D. Allylisopropylacetamide administration degrades microsomal haem but not nuclear haem. Haem does not counteract the decrease in cytochrome P-450 content caused by allylisopropylacetamide administration, but there is evidence for the formation of drug-resistant protein-bound haem in liver microsomal material under these conditions. Phenobarbital induces delta-aminolaevulinate synthetase under conditions when there is no breakdown of cytochrome P-450. On the basis of these results and those already published, a model is proposed for the regulation of delta-aminolaevulinate synthetase induction in rat liver.
| S-EPMC1177892 | biostudies-other
Project description:Acetyl coenzyme A synthetase-1 (AceCS1) catalyzes the synthesis of acetyl coenzyme A from acetate and coenzyme A and is thought to play diverse roles ranging from fatty acid synthesis to gene regulation. By using an affinity-purified antibody generated against an 18-mer peptide sequence of AceCS1 and a polyclonal antibody directed against recombinant AceCS1 protein, we examined the expression of AceCS1 in the rat brain. AceCS1 immunoreactivity in the adult rat brain was present predominantly in cell nuclei, with only light to moderate cytoplasmic staining in some neurons, axons, and oligodendrocytes. Some nonneuronal cell nuclei were very strongly immunoreactive, including those of some oligodendrocytes, whereas neuronal nuclei ranged from unstained to moderately stained. Both antibodies stained some neuronal cell bodies and axons, especially in the hindbrain. AceCS1 immunoreactivity was stronger and more widespread in the brains of 18-day-old rats than in adults, with increased expression in oligodendrocytes and neurons, including cortical pyramidal cells. Expression of AceCS1 was substantially up-regulated in neurons throughout the brain after controlled cortical impact injury. The strong AceCS1 expression observed in the nuclei of CNS cells during brain development and after injury is consistent with a role in nuclear histone acetylation and therefore the regulation of chromatin structure and gene expression. The cytoplasmic staining observed in some oligodendrocytes, especially during postnatal brain development, suggests an additional role in CNS lipid synthesis and myelination. Neuronal and axonal localization implicates AceCS1 in cytoplasmic acetylation reactions in some neurons.
| S-EPMC3047483 | biostudies-literature
Project description:BACKGROUND:ATP-sensitive K+ (KATP) channels were originally found in cardiac myocytes by Noma in 1983. KATP channels were formed by potassium ion-passing pore-forming subunits (Kir6.1, Kir6.2) and regulatory subunits SUR1, SU2A and SUR2B. A number of cells and tissues have been revealed to contain these channels including hepatocytes, but detailed localization of these subunits in different types of liver cells was still uncertain. AIM:To investigate the expression of KATP channel subunits in rat liver and their localization in different cells of the liver. METHODS:Rabbit anti-rat SUR1 peptide antibody was raised and purified by antigen immunoaffinity column chromatography. Four of Sprague-Dawley rats were used for liver protein extraction for immunoblot analysis, seven of them were used for immunohistochemistry both for the ABC method and immunofluorescence staining. Four of Wistar rats were used for the isolation of hepatic stellate cells (HSCs) and Kupffer cells for both primary culture and immunocytochemistry. RESULTS:Immunoblot analysis showed that the five kinds of KATP channel subunits, i.e. Kir6.1, Kir6.2, SUR1, SUR2A, and SUR2B, were detected in liver. Immunohistochemical staining showed that Kir6.1 and Kir6.2 were weakly to moderately expressed in parenchymal cells and sinusoidal lining cells, while SUR1, SUR2A, and SUR2B were mainly localized to sinusoidal lining cells, such as HSCs, Kupffer cells, and sinusoidal endothelial cells. Immunoreactivity for SUR2A and SUR2B was expressed in the hepatocyte membrane. Double immunofluorescence staining further showed that the pore-forming subunits Kir6.1 and/or Kir6.2 colocalized with GFAP in rat liver sections and primary cultured HSCs. These KATP channel subunits also colocalized with CD68 in liver sections and primary cultured Kupffer cells. The SUR subunits colocalized with GFAP in liver sections and colocalized with CD68 both in liver sections and primary cultured Kupffer cells. In addition, five KATP channel subunits colocalized with SE-1 in sinusoidal endothelial cells. CONCLUSION:Observations from the present study indicated that KATP channel subunits expressed in rat liver and the diversity of KATP channel subunit composition might form different types of KATP channels. This is applicable to hepatocytes, HSCs, various types of Kupffer cells and sinusoidal endothelial cells.
| S-EPMC6955576 | biostudies-literature
Project description:The porphyrinogenic drug 2-allyl-2-isopropylacetamide causes the degradation of microsomal cytochrome P-450 and inhibits the synthesis of catalase in rat liver. The inhibition of catalase synthesis follows the induction of delta-aminolaevulinate synthetase and the consequent overproduction of haem. The allylisopropylacetamide-mediated breakdown of cytochrome P-450 is a rapid event and has a reciprocal relationship to the pattern of delta-aminolaevulinate synthetase induction. Breakdown of cytochrome P-450 appears to be one of the conditions leading to the ;derepression' of delta-aminolaevulinate synthetase.
| S-EPMC1178697 | biostudies-other
Project description:1. delta-Aminolaevulate dehydratase (EC 4.2.1.24) was purified 80-fold from tobacco leaves and its properties were studied. 2. The enzyme had optimum pH7.4 in potassium phosphate buffer, K(m)6.25x10(-4)m at 37 degrees and pH7.4, optimum temperature 45 degrees and an activation energy of 11100 cal./mole. 3. The enzyme lost activity when prepared in the absence of cysteine, and this activity was only partly restored by the later addition of thiols. Reagents for thiol groups inactivated the enzyme. 4. Mg(2+) was essential for activity, and EDTA and Fe(2+) were inhibitory; Mn(2+) was an activator or an inhibitor depending on the concentration.
| S-EPMC1184859 | biostudies-other
Project description:Accurate knowledge of the intracellular location of proteins is important for numerous areas of biomedical research including assessing fidelity of putative protein-protein interactions, modeling cellular processes at a system-wide level and investigating metabolic and disease pathways. Many proteins have not been localized, or have been incompletely localized, partly because most studies do not account for entire subcellular distribution. Thus, proteins are frequently assigned to one organelle whereas a significant fraction may reside elsewhere. As a step toward a comprehensive cellular map, we used subcellular fractionation with classic balance sheet analysis and isobaric labeling/quantitative mass spectrometry to assign locations to >6000 rat liver proteins. We provide quantitative data and error estimates describing the distribution of each protein among the eight major cellular compartments: nucleus, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, Golgi, plasma membrane and cytosol. Accounting for total intracellular distribution improves quality of organelle assignments and assigns proteins with multiple locations. Protein assignments and supporting data are available online through the Prolocate website (http://prolocate.cabm.rutgers.edu). As an example of the utility of this data set, we have used organelle assignments to help analyze whole exome sequencing data from an infant dying at 6 months of age from a suspected neurodegenerative lysosomal storage disorder of unknown etiology. Sequencing data was prioritized using lists of lysosomal proteins comprising well-established residents of this organelle as well as novel candidates identified in this study. The latter included copper transporter 1, encoded by SLC31A1, which we localized to both the plasma membrane and lysosome. The patient harbors two predicted loss of function mutations in SLC31A1, suggesting that this may represent a heretofore undescribed recessive lysosomal storage disease gene.
| S-EPMC5294208 | biostudies-literature
Project description:The action of haem, haemoglobin and other haemoproteins on crude and purified delta-aminolaevulate dehydratase of human erythrocyte is described. The results show a feedback inhibition by haem of porphyrin synthesis at the level of erythrocyte delta-aminolaevulate dehydratase. Some kinetic characteristics of this inhibition are described.
| S-EPMC1270139 | biostudies-other