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M Sase

Publications and source records attributed to M Sase.

At least 37 records · Page 2Linked to original sources
PubMed1989

Identification of essential arginine residue(s) for Mg-ATP binding of human argininosuccinate synthetase.

Human argininosuccinate synthetase (ASS) activity was found to be inactivated by alpha-dicarbonyls such as 1,2-cyclohexanedione and phenylglyoxal in accordance with pseudo first-order kinetics. The enzyme was almost completely protected from this inactivation by Mg-ATP and partially by its analogues. The strongest protective effect against inactivation was found with Mg-ATP, followed by Mg-ADP, AMP, adenosine and Mg-inorganic pyrophosphate. These results suggest the importance of arginine residue(s) for Mg-ATP binding. We determined the amino acid sequence of the peptide with the highest specific radioactivity derived from ASS which had been labeled with [14C]phenylglyoxal and then cleaved by cyanogen bromide treatment. The sequence obtained, PEFYNRFKGRNDLM, corresponds to residues 148-161 of the amino acid sequence deduced from the cDNA nucleotide sequence determined by Bock et al. [Nucleic Acids Res 11:6505-6512, 1983], and has a high homology with the sequences of ATP-binding sites proposed for several ATP-requiring enzymes.

Adenosine Triphosphate↗
PubMed1988

The heterogeneous distribution of argininosuccinate synthetase in the liver of type II citrullinemic patients. Its specificity and possible clinical implications.

The authors analyzed the heterogeneous distribution of hepatic argininosuccinate synthetase of type II citrullinemia in reference to its specificity and clinical implications. The low content of the enzyme in the liver of type II citrullinemic patients is associated with two kinds of the enzyme distribution that can be visualized by means of an immunohistochemical method (Saheki and colleagues. Biomed Res 1983;4:235-238). Among the 25 cases of type II citrullinemia examined, 11 exhibited homogeneous distribution of the enzyme, as in the control livers. On the other hand, 14 presented the clustered distribution, in which the hepatocytes stained positively with antisera to argininosuccinate synthetase formed a cluster among the poorly stained cells. No clustered distribution of the enzyme was present in the liver of control patients either with or without liver diseases. No clustered distribution of arginase and aldolase B was observed even in the liver of type II citrillinemic patients. These results suggest that clustered distribution is specific to argininosuccinate synthetase in the liver of type II citrullinemic patients. From considerations concerning the heterogeneous distribution of the enzyme and certain clinical parameters as well, the authors suggest that the clustered type in type II citrullinemia has a less favorable prognosis with regard to fatality.

Argininosuccinate Synthase↗
PubMed1988

Partial purification and properties of neutral PTHase from the cytosolic fraction of rat renal cortex.

A possible new enzyme, a cytosolic neutral PTH-degrading enzyme previously described by us, was purified by ammonium sulfate fractionation, Sephadex G-200 column chromatography and DEAE cellulose column chromatography from the 100,000 x g supernatant of rat kidney. Three active peaks (designated P-I, P-II and P-III) were obtained through a DEAE cellulose chromatographic column. These three activity peaks were interchangeable on rechromatography. Further characterization of the major P-II fraction was attempted. When PTH was used as the substrate, this enzyme preparation (P-II) was inhibited by Ca2+, ATP and glutathione (GSH), but not by trypsin inhibitor, PMSF, E-64, leupeptin, chymostatin or pepstatin. This enzyme preparation could hardly hydrolyze several synthetic analogs containing MCA but not Leu-MCA and Z-Phe-Arg-MCA. When Z-Phe-Arg-MCA was used as the substrate, this enzyme preparation was activated by ATP and GSH, while no activation was induced when PTH was used. These results indicate that the neutral PTH-degrading enzyme seems to represent a new PTHase capable of specifically splitting PTH at certain locations.

Animals↗
PubMed1986

Absence of argininosuccinate lyase protein in the liver of two patients with argininosuccinic aciduria.

The enzyme defects in two cases of argininosuccinic aciduria were examined at the molecular level by enzymatic and immunological methods. No argininosuccinate lyase activity was detected in the liver or erythrocytes of either patient nor in the kidney or brain of one of the patients even in the presence of high concentrations of the substrate. The titration curve of antiserum to human argininosuccinate lyase with the liver extract from a control subject was not affected by the addition of the liver extracts from one of the patients. Double immunodiffusion analysis revealed a single precipitin line between the purified antiserum and the liver extract from a control, but no precipitin lines between the antisera and the liver extracts from the two patients. These results indicate a complete or almost complete defect of an immunologically cross-reactive material in the liver of the patients.

Amino Acid Metabolism, Inborn Errors↗
PubMed1986

Parathyroid hormone-degrading enzyme of high molecular weight in the cytosol of rat renal cortical cells.

Using unlabeled bovine parathyroid hormone (b-PTH) as the substrate, the PTH-degrading activity in the 100,000 x g supernatant of rat renal cortex was examined. The PTH-degrading activity showed the highest peak at pH 7.25, along with 3 minor peaks at pH 4.5, 6.0 and 8.5. The neutral PTH-degrading activity of the 100,000 x g supernatant (pH 7.25) was eluted at V0 in Sephadex G-200 gel filtration corresponding to a high molecular weight. The neutral PTH-degrading activity was inhibited by ATP and calcium, but the acid PTH-degrading activity (pH 4.5) was slightly activated by ATP and was uninfluenced by calcium. The cytosolic neutral PTH-degrading activity was not inhibited by PMSF, trypsin inhibitor, E-64, chymostatin, leupeptin or pepstatin, whereas the acid PTH-degrading activity was inhibited by pepstatin, leupeptin, trypsin inhibitor and chymostatin. The neutral and acid PTH-degrading activities most probably depend on different enzymes. The neutral PTH-degrading enzyme is unlike any of the PTH-degrading enzymes so far reported.

Adenosine Triphosphate↗
PubMed1985

Level of translatable messenger RNA coding for argininosuccinate synthetase in the liver of the patients with quantitative-type citrullinemia.

The translation activity of mRNA coding for argininosuccinate synthetase in total RNA extracted from the liver of three patients with quantitative-type citrullinemia was determined using a cell-free translation system. In two patients, the hepatic content of the enzyme was about 20% of the control value, whereas translatable mRNA level for the enzyme was similar to or slightly lower than those of control livers. In the third patient, the enzyme content was about 50% of the control value, and mRNA activity for the enzyme was low normal. These results indicate that at least in the first two patients, the decrease in the enzyme protein is due either to increased degradation of the enzyme or to decreased translation in the patient's liver.

Adult↗
PubMed1981

[A study on the mechanism of production and secretion of HPL (author's transl)].

Our preliminary data suggest that HPL was present in the largest quantity in chorionic villi of 16-18 weeks of pregnancy but the concentration of HPL in mother blood was maximum at 30-40 weeks of pregnancy. To clarify the discrepancy of term of those maximum values, the following experiments were done. The immuno-precipitate caused by the reaction with anti-HPL serum in the crude extract from chorionic villi incubated with MEM medium containing [3H]-leucine was subjected to SDS gel electrophoresis. Three radioactive bands were observed. Their molecular weights were 22000, 29000 and 48000, native HPL is 22000 molecular weights and other heavier molecular weights protein are surmised pre- or pro-HPL. Native HPL was few in 30 min. incubated cases but increased in over night incubated cases. Other heavier molecular weights protein changed into native HPL with the lapse of time. The concentration of HPL in mother blood is surmised to reflect the production of two pro-HPL is syncytium cells, change into free HPL and furthermore their secretion.

Blood Protein Electrophoresis↗