Hydrolysis of Retinol Palmitate by Rat Liver

1. The 105000g supernatant fraction of rat liver catalyses the incorporation of ribonucleotides from ribonucleoside triphosphates into polyribonucleotide material. The reaction requires Mg2+ ions and is enhanced by the addition of an ATP-generating system and RNA, ATP, UTP and CTP but not GTP are utilized in this reaction. In the case of UTP, the product is predominantly a homopolymer containing 2–3 uridine residues, and there is evidence that these may be added to the 3′-hydroxyl ends of RNA or oligoribonucleotide primers. 2. The microsome fraction of rat liver incorporates ribonucleotides from ATP, GTP, CTP and UTP into polyribonucleotide material. This reaction requires Mg2+ ions and is enhanced slightly by the addition of an ATP-generating system, and by RNA but not DNA. Supplementation of the reaction mixture with the three complementary ribonucleoside 5′-triphosphates greatly increases the utilization of a single labelled ribonucleoside 5′-triphosphate. The optimum pH is in the range 7·0–8·5, and the reaction is strongly inhibited by inorganic pyrophosphate and to a much smaller degree by inorganic orthophosphate. It is not inhibited by actinomycin D or by deoxyribonuclease. In experiments with [32P]UTP in the absence of ATP, GTP and CTP, 80–90% of 32P was recovered in UMP-2′ or −3′ after alkaline hydrolysis of the reaction product. When the reaction mixture was supplemented with ATP, GTP and CTP, however, about 40% of the 32P was recovered in nucleotides other than UMP-2′ or −3′. Although the reactions seem to lead predominantly to the synthesis of homopolymers, the possibility of some formation of some heteropolymer is not completely excluded.

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The roles of phospholipase D and a GTP-binding protein in guanosine 5′-[γ-thio]triphosphate-stimulated hydrolysis of phosphatidylcholine in rat liver plasma membranes

Biochemical Journal ◽

10.1042/bj2720749 ◽

1990 ◽

Vol 272 (3) ◽

pp. 749-753 ◽

Cited By ~ 20

Author(s):

K M Hurst ◽

B P Hughes ◽

G J Barritt

Keyword(s):

Rat Liver ◽

Phospholipase D ◽

Plasma Membranes ◽

Regulatory Protein ◽

Gtp Binding ◽

Liver Plasma Membranes ◽

Low Concentrations ◽

Rat Liver Plasma Membranes ◽

Triton X ◽

Hydrolysis Of

1. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]) stimulated by 50% the rate of release of [3H]choline and [3H]phosphorylcholine in rat liver plasma membranes labelled with [3H]choline. About 70% of the radioactivity released in the presence of GTP[S] was [3H]choline and 30% was [3H]phosphorylcholine. 2. The hydrolysis of phosphorylcholine to choline and the conversion of choline to phosphorylcholine did not contribute to the formation of [3H]choline and [3H]phosphorylcholine respectively. 3. The release of [3H]choline from membranes was inhibited by low concentrations of SDS or Triton X-100. Considerably higher concentrations of the detergents were required to inhibit the release of [3H]phosphorylcholine. 4. Guanosine 5′-[beta gamma-imido]triphosphate and guanosine 5′-[alpha beta-methylene]triphosphate, but not adenosine 5′-[gamma-thio]-triphosphate, stimulated [3H]choline release to the same extent as did GTP[S]. The GTP[S]-stimulated [3H]choline release was inhibited by guanosine 5′-[beta-thio]diphosphate, GDP and GTP but not by GMP. 5. It is concluded that, in rat liver plasma membranes, (a) GTP[S]-stimulated hydrolysis of phosphatidylcholine is catalysed predominantly by phospholipase D with some contribution from phospholipase C, and (b) the stimulation of phosphatidylcholine hydrolysis by GTP[s] occurs via a GTP-binding regulatory protein.

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Decreased Hydrolysis of Solvent-Derived Oxa Acyl-CoA by Rat Liver Acyl-CoA Hydrolases

Biochemical Society Transactions ◽

10.1042/bst028a437c ◽

2000 ◽

Vol 28 (5) ◽

pp. A437-A437

Author(s):

S. D. Panuganti ◽

J. R. Frybarger ◽

K. H. Moore

Keyword(s):

Rat Liver ◽

Hydrolysis Of

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Hydrolysis of Nucleoside Di- and Tri-phosphates by Alkaline Inorganic Pyrophosphatases of Rat Liver and Yeast

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a129234 ◽

1970 ◽

Vol 67 (1) ◽

pp. 59-63 ◽

Cited By ~ 7

Author(s):

MASACHIKA IRIE ◽

ATSUKO YABUTA ◽

TAHEI NEGI ◽

KENKICHI TOMITA

Keyword(s):

Rat Liver ◽

Hydrolysis Of

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Studies on Cathepsins of Rat Liver Lysosomes. III. Hydrolysis of Peptides, and Inactivation of Angiotensin and Bradykinin by Cathepsin A

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a131325 ◽

1976 ◽

Vol 80 (4) ◽

pp. 659-669 ◽

Cited By ~ 19

Author(s):

Keiichi MATSUDA

Keyword(s):

Rat Liver ◽

Liver Lysosomes ◽

Rat Liver Lysosomes ◽

Hydrolysis Of

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Stereoselective hydrolysis of xenobiotic esters by different cell lines from rat liver and hepatoma and its application to chiral prodrugs for designated growth suppression of cancer cells

Chirality ◽

10.1002/chir.530070418 ◽

1995 ◽

Vol 7 (4) ◽

pp. 297-304 ◽

Cited By ~ 7

Author(s):

Yu-Ichi Kageyama ◽

Yoshimitsu Yamazaki ◽

Adel S. Afify ◽

Yoshikatsu Ogawa ◽

Tomoko Okada ◽

...

Keyword(s):

Cancer Cells ◽

Cell Lines ◽

Rat Liver ◽

Growth Suppression ◽

Stereoselective Hydrolysis ◽

Hydrolysis Of

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Purification of two distinct types of phosphoinositide-specific phospholipase C from rat liver. Enzymological and structural studies

Biochemical Journal ◽

10.1042/bj2560453 ◽

1988 ◽

Vol 256 (2) ◽

pp. 453-459 ◽

Cited By ~ 21

Author(s):

O Nakanishi ◽

Y Homma ◽

H Kawasaki ◽

Y Emori ◽

K Suzuki ◽

...

Keyword(s):

Amino Acid ◽

Phospholipase C ◽

Rat Liver ◽

Peptide Mapping ◽

Polyacrylamide Gel Electrophoresis ◽

Liver Homogenate ◽

Amino Acid Sequences ◽

Dependent Manner ◽

Phosphatidylinositol 4 ◽

Hydrolysis Of

Two kinds of phosphoinositide-specific phospholipase C (PLC) were purified from rat liver by acid precipitation and several steps of column chromatography. About 50% of the activity could be precipitated when the pH of the liver homogenate was lowered to pH 4.7. The redissolved precipitate yielded two peaks, PLC I and PLC II, in an Affi-gel Blue column, and each was further purified to homogeneity by three sequential h.p.l.c. steps, which were different for the two enzymes. The purified PLC I and PLC II had estimated Mr values of 140,000 and 71,000 respectively on SDS/polyacrylamide-gel electrophoresis. Both enzymes hydrolysed phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) in a Ca2+- and pH-dependent manner. PLC I was most active at 10 microM- and 0.1 mM-Ca2+ for hydrolysis of PI and PIP2 respectively, whereas PLC II showed the highest activity at 5 mM- and 10 microM-Ca2+ for that of PI and PIP2 respectively. The optimal pH of the two enzymes also differed with substrates or Ca2+ concentration, in the range pH 5.0-6.0. Hydrolysis of phosphoinositides by these enzymes was completely inhibited by Hg2+ and was affected by other bivalent cations. From data obtained by peptide mapping and partial amino acid sequencing, it was clarified that PLC I and PLC II had distinct structures. Moreover, partial amino acid sequences of three proteolytic fragments of PLC I completely coincided with those of PLC-148 [Stahl, Ferenz, Kelleher, Kriz & Knopf (1988) Nature (London) 332, 269-272].

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