Hydrolysis by horse muscle acylphosphatase of (Ca2+ + Mg2+)-ATPase phosphorylated intermediate

Stefani, Massimo; Liguri, Gianfranco; Berti, Andrea; Nassi, Paolo; Ramponi, Giampietro

doi:10.1016/0003-9861(81)90120-x

Cited by 37 publications

(16 citation statements)

References 15 publications

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“…is a basic enzyme which catalyses the hydrolysis of acylphosphates both synthetic, such as benzoylphosphate [1], and of physiological interest, such as acetylphosphate, carbamoylphosphate, succinylphosphate, 1,3-diphosphoglycerate, and the phosphorylated intermediate formed during the activity of membrane pump ATPases [2][3][4][5][6][7]. Acylphosphatase is widely distributed in vertebrate tissues and organs as two isoenzymes displaying about 55% amino acid sequence homology.…”

Section: Introductionmentioning

confidence: 99%

Properties of N‐terminus truncated and C‐terminus mutated muscle acylphosphatases

et al. 1995

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Enzymatic activity and structure of N-terminus truncated and C-terminus substituted muscle acylphosphatase mutants were investigated by kinetic studies under different conditions and tH NMR spectroscopy, respectively. The N-terminus truncated mutant lacked the first six residues (A6), whereas arginine 97 and tyrosine 98 were replaced by glutamine giving two C-terminus substituted mutants (R97Q and Y98Q, respectively). All acylphosphatase forms were obtained by modifications of a synthetic gene coding for the human muscle enzyme which was expressed in E. coli. The A6 deletion mutant elicited a reduced specific activity and a native-like structure. The kinetic and structural properties of R97Q and Y98Q mutants indicate a possible role of Arg-97 in the stabilisation of the active site correct conformation, most likely via back-bone and side chain interactions with Arg-23, the residue involved in phosphate binding by the enzyme. This study also suggests a possible involvement of Tyr-98 in the stabilisation of the acylphosphatase overall structure.

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Section: Introductionmentioning

confidence: 99%

Properties of N‐terminus truncated and C‐terminus mutated muscle acylphosphatases

et al. 1995

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“…For example, this enzyme causes an uncoupling of glycolytic ATP generation, since it catalyses the hydrolysis of 1,3-bisphosphoglycerate and causes an increase in the glycolytic rate [9,33,34]. Moreover, the 3phosphoglycerate-dependent ATPase activity of acylphosphatase parallels the acylphosphatase-dependent increase in membrane Na+/K+-and Ca2+-ATPase activities [4][5][6]. Both of these actions of acylphosphatase result in a loss of ATP-free energy and heat production; this mechanism may be responsible for thyroid hormone-dependent hyperthermia.…”

Section: Discussionmentioning

confidence: 99%

“…They exhibit similar substrate specificity and kinetic properties, except that the erythrocyte isoenzyme appears to have higher catalytic activity. It has been demonstrated that the muscle isoenzyme is able to hydrolyse the carboxyl-phosphate bond formed in membrane pumps such as the Na+/K+-ATPase of the plasma membrane and the Ca2+/Mg2+-ATPase of the sarcoplasmic reticulum [4,5]. The erythrocyte isoenzyme stimulates Ca2+-ATPase activity in red blood cell plasma membranes, lowering Ca2+ transport and thus acting as a pump inhibitor [6].…”

Section: Introductionmentioning

confidence: 99%

Differential modulation of expression of the two acylphosphatase isoenzymes by thyroid hormone

Chiarugi

Raugei

Marzocchini

et al. 1995

Biochemical Journal

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The modulation of expression of the skeletal muscle and erythrocyte acylphosphatase isoenzymes by thyroid hormone has been investigated. Our results indicate a differential regulation of the two enzymic isoforms by tri-iodothyronine (T3) in K562 cells in culture: an increase in the specific mRNA during T3-stimulation is shown only for the skeletal muscle isoenzyme. A fast and transient T3 induction of the accumulation of the specific mRNA can be observed, reaching a maximum 8 h after hormone treatment and then rapidly decreasing almost to the steady-state level after 24 h. A nuclear run-on assay was performed to explore the mechanisms of this regulation. These studies indicate that T3 induction of skeletal muscle acylphosphatase mRNA is due, at least in part, to a fast and transient increase in the rate of gene transcription, within 4 h after hormone administration. A very rapid decrease is then observed within a further 2 h. T3-dependent accumulation of the mRNA for the skeletal muscle acylphosphatase requires ongoing protein synthesis, as confirmed by inhibition with cycloheximide or puromycin. These findings indicate that the transcriptional regulation of the gene may be indirect.

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“…Acylphosphatase (EC 3.6.1.7) is a very basic, small enzyme (MW 11,365, horse muscle enzyme) which catalyzes the hydrolysis of compounds containing a carboxylphosphate bond either synthetic or physiologically important, such as 1,3-bisphosphoglycerate, carbamoylphosphate, succinylphosphate, and the /3-aspartylphosphate formed during the action of membrane ion pumps (Ramponi et aL, 1966a;Ramponi, 1975;Berti et al, 1977;Stefani et al, 1981;Hokin et al, 1965). The enzyme elicits strict specificity for carboxylphosphate bond hydrolysis, since it appears inactive on phosphate monoester bond, and is not able to 1 Department of Biochemical Sciences, University of Florence, Florence, Italy.…”

Section: Introductionmentioning

confidence: 99%

Properties of Cys21-mutated muscle acylphosphatases

et al. 1996

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Cys21 is an invariant residue in muscle acylphosphatases, but is absent in the erythrocyte isozymes. To assess the importance of this residue in the muscle isozymes for catalytic, structural, and stability properties, two gene mutants have been prepared by oligonucleotide-directed mutagenesis and expressed in Escherichia coli cells; in these mutants, the codon for Cys21 was replaced by those for Ser and Ala, respectively. The two mutant enzymes, purified by immunoaffinity chromatography, showed kinetic and structural properties similar to those of the wild-type recombinant enzyme; however, the specific activity of the two mutants, especially that of the C21A mutant, was lower. The urea and thermal stabilities of the mutant enzymes were reduced with respect to those of the wild-type form, contrary to the susceptibility to inactivation by mercuric ions. The reported data support the possibility that Cys21 is involved in the stabilization of the enzyme active-site conformation.

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Hydrolysis by horse muscle acylphosphatase of (Ca2+ + Mg2+)-ATPase phosphorylated intermediate

Cited by 37 publications

References 15 publications

Properties of N‐terminus truncated and C‐terminus mutated muscle acylphosphatases

Properties of N‐terminus truncated and C‐terminus mutated muscle acylphosphatases

Differential modulation of expression of the two acylphosphatase isoenzymes by thyroid hormone

Properties of Cys21-mutated muscle acylphosphatases

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