Acyl-CoA thioesterases are a group of enzymes that catalyze the hydrolysis of acyl-CoAs to the free fatty acid and coenzyme A (CoASH), providing the potential to regulate intracellular levels of acyl-CoAs, free fatty acids and CoASH. Displays high levels of activity on medium- and long chain acyl CoAs.
Computer-based approaches identified PTE2 as a candidate human peroxisomal acyl-CoA thioesterase gene. The PTE2 gene product is highly similar to the rat cytosolic and mitochondrial thioesterases, CTE1 and MTE1, respectively, and terminates in a tripeptide sequence, serine-lysine-valine(COOH), that resembles the consensus sequence for type-1 peroxisomal targeting signals. PTE2 was targeted to peroxisomes and recombinant PTE2 showed intrinsic acyl-CoA thioesterase activity with a pH optimum of 8.5. A comparison of PTE2 and PTE1 thioesterase activities across multiple acyl-CoA substrates indicated that while PTE1 was most active on medium-chain acyl-CoAs, with little activity on long-chain acyl-CoAs, PTE2 displayed high activity on medium- and long-chain acyl-CoAs. The identification of PTE2 therefore offers an explanation for the observed long-chain acyl-CoA thioesterase activity of mammalian peroxisomes.
Computer-based approaches identified PTE2 as a candidate human peroxisomal acyl-CoA thioesterase gene. The PTE2 gene product is highly similar to the rat cytosolic and mitochondrial thioesterases, CTE1 and MTE1, respectively, and terminates in a tripeptide sequence, serine-lysine-valine(COOH), that resembles the consensus sequence for type-1 peroxisomal targeting signals. PTE2 was targeted to peroxisomes and recombinant PTE2 showed intrinsic acyl-CoA thioesterase activity with a pH optimum of 8.5. A comparison of PTE2 and PTE1 thioesterase activities across multiple acyl-CoA substrates indicated that while PTE1 was most active on medium-chain acyl-CoAs, with little activity on long-chain acyl-CoAs, PTE2 displayed high activity on medium- and long-chain acyl-CoAs. The identification of PTE2 therefore offers an explanation for the observed long-chain acyl-CoA thioesterase activity of mammalian peroxisomes.
The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important, as imbalances in lipid metabolism have serious consequences for human health. Acyl-coenzyme A (CoA) thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We previously identified and characterized a mouse ACOT gene cluster comprised of six genes that apparently arose by gene duplications encoding acyl-CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2), and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three genes (ACOT1, ACOT2, and ACOT4) coding for full-length thioesterase proteins, of which only one is peroxisomal (ACOT4). We therefore set out to characterize the human genes, and we show here that the human ACOT4 protein catalyzes the activities of three mouse peroxisomal ACOTs (ACOT3, 4, and 5), being active on succinyl-CoA and medium to long chain acyl-CoAs, while ACOT1 and ACOT2 carry out similar functions to the corresponding mouse genes. These data strongly suggest that the human ACOT4 gene has acquired the functions of three mouse genes by a functional convergent evolution that also provides an explanation for the unexpectedly low number of human genes.
Interacting selectively and non-covalently with one or more specific sites on a receptor molecule, a macromolecule that undergoes combination with a hormone, neurotransmitter, drug or intracellular messenger to initiate a change in cell function.
Evidence
1:
Inferred from Physical InteractionUniProtKB
Most proteins are targeted to the peroxisomal matrix by virtue of a peroxisomal targeting signal-1 (PTS1), a short carboxy-terminal sequence specifically recognized by the PTS1 receptor Pex5p. We had previously developed a model that allowed the estimation of the affinities of many PTS1 sequences within the human proteome for Pex5p that revealed a wide range of predicted affinities. We have now experimentally determined the affinities of the PTS1-containing peptides from 42 proteins from the human proteome for Pex5p and show that these range over 4 orders of magnitude. These affinities correlate reasonably well with the predicted values and are substantially more precise. In an attempt to provide a possible explanation for the wide range of PTS1-Pex5p affinities, we compared these affinities with mRNA levels (as a proxy for rates of protein production) of the genes encoding these proteins in 79 human tissues and cell types. We note that high affinity PTS1-Pex5p interactions tend to correspond to proteins encoded by genes expressed at relatively low levels, whereas lower affinity PTS1-Pex5p interactions tend to correspond to proteins encoded by genes exhibiting higher levels and wider ranges of expression. Further analysis revealed that these relationships are consistent with the notion that a relatively uniform pool of protein-Pex5p complexes is maintained for appropriate peroxisome assembly.
The chemical reactions and pathways involving acyl-CoA, any derivative of coenzyme A in which the sulfhydryl group is in thiolester linkage with an acyl group.
Computer-based approaches identified PTE2 as a candidate human peroxisomal acyl-CoA thioesterase gene. The PTE2 gene product is highly similar to the rat cytosolic and mitochondrial thioesterases, CTE1 and MTE1, respectively, and terminates in a tripeptide sequence, serine-lysine-valine(COOH), that resembles the consensus sequence for type-1 peroxisomal targeting signals. PTE2 was targeted to peroxisomes and recombinant PTE2 showed intrinsic acyl-CoA thioesterase activity with a pH optimum of 8.5. A comparison of PTE2 and PTE1 thioesterase activities across multiple acyl-CoA substrates indicated that while PTE1 was most active on medium-chain acyl-CoAs, with little activity on long-chain acyl-CoAs, PTE2 displayed high activity on medium- and long-chain acyl-CoAs. The identification of PTE2 therefore offers an explanation for the observed long-chain acyl-CoA thioesterase activity of mammalian peroxisomes.
The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important, as imbalances in lipid metabolism have serious consequences for human health. Acyl-coenzyme A (CoA) thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We previously identified and characterized a mouse ACOT gene cluster comprised of six genes that apparently arose by gene duplications encoding acyl-CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2), and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three genes (ACOT1, ACOT2, and ACOT4) coding for full-length thioesterase proteins, of which only one is peroxisomal (ACOT4). We therefore set out to characterize the human genes, and we show here that the human ACOT4 protein catalyzes the activities of three mouse peroxisomal ACOTs (ACOT3, 4, and 5), being active on succinyl-CoA and medium to long chain acyl-CoAs, while ACOT1 and ACOT2 carry out similar functions to the corresponding mouse genes. These data strongly suggest that the human ACOT4 gene has acquired the functions of three mouse genes by a functional convergent evolution that also provides an explanation for the unexpectedly low number of human genes.
The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important, as imbalances in lipid metabolism have serious consequences for human health. Acyl-coenzyme A (CoA) thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We previously identified and characterized a mouse ACOT gene cluster comprised of six genes that apparently arose by gene duplications encoding acyl-CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2), and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three genes (ACOT1, ACOT2, and ACOT4) coding for full-length thioesterase proteins, of which only one is peroxisomal (ACOT4). We therefore set out to characterize the human genes, and we show here that the human ACOT4 protein catalyzes the activities of three mouse peroxisomal ACOTs (ACOT3, 4, and 5), being active on succinyl-CoA and medium to long chain acyl-CoAs, while ACOT1 and ACOT2 carry out similar functions to the corresponding mouse genes. These data strongly suggest that the human ACOT4 gene has acquired the functions of three mouse genes by a functional convergent evolution that also provides an explanation for the unexpectedly low number of human genes.
The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important, as imbalances in lipid metabolism have serious consequences for human health. Acyl-coenzyme A (CoA) thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We previously identified and characterized a mouse ACOT gene cluster comprised of six genes that apparently arose by gene duplications encoding acyl-CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2), and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three genes (ACOT1, ACOT2, and ACOT4) coding for full-length thioesterase proteins, of which only one is peroxisomal (ACOT4). We therefore set out to characterize the human genes, and we show here that the human ACOT4 protein catalyzes the activities of three mouse peroxisomal ACOTs (ACOT3, 4, and 5), being active on succinyl-CoA and medium to long chain acyl-CoAs, while ACOT1 and ACOT2 carry out similar functions to the corresponding mouse genes. These data strongly suggest that the human ACOT4 gene has acquired the functions of three mouse genes by a functional convergent evolution that also provides an explanation for the unexpectedly low number of human genes.
Computer-based approaches identified PTE2 as a candidate human peroxisomal acyl-CoA thioesterase gene. The PTE2 gene product is highly similar to the rat cytosolic and mitochondrial thioesterases, CTE1 and MTE1, respectively, and terminates in a tripeptide sequence, serine-lysine-valine(COOH), that resembles the consensus sequence for type-1 peroxisomal targeting signals. PTE2 was targeted to peroxisomes and recombinant PTE2 showed intrinsic acyl-CoA thioesterase activity with a pH optimum of 8.5. A comparison of PTE2 and PTE1 thioesterase activities across multiple acyl-CoA substrates indicated that while PTE1 was most active on medium-chain acyl-CoAs, with little activity on long-chain acyl-CoAs, PTE2 displayed high activity on medium- and long-chain acyl-CoAs. The identification of PTE2 therefore offers an explanation for the observed long-chain acyl-CoA thioesterase activity of mammalian peroxisomes.
The maintenance of cellular levels of free fatty acids and acyl-CoAs, the activated form of free fatty acids, is extremely important, as imbalances in lipid metabolism have serious consequences for human health. Acyl-coenzyme A (CoA) thioesterases (ACOTs) hydrolyze acyl-CoAs to the free fatty acid and CoASH, and thereby have the potential to regulate intracellular levels of these compounds. We previously identified and characterized a mouse ACOT gene cluster comprised of six genes that apparently arose by gene duplications encoding acyl-CoA thioesterases with localizations in cytosol (ACOT1), mitochondria (ACOT2), and peroxisomes (ACOT3-6). However, the corresponding human gene cluster contains only three genes (ACOT1, ACOT2, and ACOT4) coding for full-length thioesterase proteins, of which only one is peroxisomal (ACOT4). We therefore set out to characterize the human genes, and we show here that the human ACOT4 protein catalyzes the activities of three mouse peroxisomal ACOTs (ACOT3, 4, and 5), being active on succinyl-CoA and medium to long chain acyl-CoAs, while ACOT1 and ACOT2 carry out similar functions to the corresponding mouse genes. These data strongly suggest that the human ACOT4 gene has acquired the functions of three mouse genes by a functional convergent evolution that also provides an explanation for the unexpectedly low number of human genes.
Enzyme which catalyzes hydrolysis reaction, i.e. the addition of the hydrogen and hydroxyl ions of water to a molecule with its consequent splitting into two or more simpler molecules.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.