scholarly journals Tryptophan 5-hydroxylase in rat intestine

1973 ◽  
Vol 131 (2) ◽  
pp. 375-380 ◽  
Author(s):  
T. Noguchi ◽  
M. Nishino ◽  
R. Kido
Keyword(s):  
Enzyme Activity ◽  
Small Intestine ◽  
Physiological Significance ◽  
Rat Small Intestine ◽  
Rat Intestine ◽  
Ph Optimum ◽  
Full Activity

Tryptophan 5-hydroxylase was partially purified from rat small intestine and characterized. The enzyme activity was mainly localized in the distal one-fourth of the small intestine. The enzyme required Fe2+, 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine and oxygen for full activity. The pH optimum of the reaction was 8.0. The hydroxylation rate of d-tryptophan by the enzyme was one-third that of l-tryptophan. l-Phenylalanine and l-tyrosine could not serve as substrates. The physiological significance of the enzyme is discussed.

scholarly journals Effects of short-term insulin deficiency on lipogenesis and cholesterol synthesis in rat small intestine and liver in vivo

1985 ◽  
Vol 231 (1) ◽  
pp. 221-223 ◽  
Author(s):  
D H Williamson ◽  
V Ilic ◽  
J Hughes
Keyword(s):  
Small Intestine ◽  
Cholesterol Synthesis ◽  
Physiological Significance ◽  
Oral Glucose ◽  
Rat Small Intestine ◽  
Insulin Deficiency ◽  
Rat Intestine ◽  
Short Term ◽  
Glucose Loading

The rate of lipogenesis in rat intestine increased on oral glucose loading and decreased after induction of acute insulin deficiency with streptozotocin. The latter effects could be partially reversed by administration of insulin. Parallel changes in the rate of lipogenesis were found in liver. In contrast, insulin deficiency did not alter the rate of cholesterol synthesis in intestine, but decreased it in liver. The physiological significance of the regulation of intestinal lipogenesis by insulin is discussed.

Apolipoprotein A-IV synthesis in rat intestine: regulation by dietary triglyceride

1987 ◽  
Vol 252 (5) ◽  
pp. G662-G666 ◽  
Author(s):  
T. F. Apfelbaum ◽  
N. O. Davidson ◽  
R. M. Glickman
Keyword(s):  
Protein Synthesis ◽  
Small Intestine ◽  
Total Protein ◽  
Mrna Levels ◽  
Rat Small Intestine ◽  
Rat Intestine ◽  
Apolipoprotein A ◽  
Rat Enterocytes

Apolipoprotein A-IV (apoA-IV) synthesis rates were measured in vivo in rat enterocytes by immunoprecipitation after administration of [3H]leucine into in situ loops of jejunum and ileum. Basal apoA-IV synthesis rates (percent total protein synthesis) were significantly higher in jejunal enterocytes (2.05 +/- 0.54%) compared with ileal enterocytes (0.48 +/- 0.32%) from the same fasted animals. After an acute triglyceride bolus, significant and sustained elevations of apoA-IV synthesis rates were seen in both jejunal and ileal enterocytes with maximal effects noted at 4-6 h. Animals fed diets containing 30% wt/wt triglyceride as saturated (SF) or polyunsaturated (UF) fats for 6 wk had similarly increased rates of apoA-IV synthesis in jejunal enterocytes with both SF (3.73 +/- 0.83%) and UF (3.33 +/- 0.64%) but no change in ileal enterocytes. By contrast, animals consuming a fat-free diet for 3 wk had jejunal apoA-IV synthesis rates indistinguishable from basal values (2.40 +/- 0.45%). Translatable intestinal mRNA levels for pre-apoA-IV after triglyceride increased in parallel to synthesis rates with a 50% increase in jejunum and a 350% increase in ileum observed at 4-6 h. These results suggest that apoA-IV synthesis by rat small intestine increases in response to acute and chronic dietary triglyceride, is maintained in the absence of dietary triglyceride, and may be under pretranslational control.

Covalent structure of a group-specific protease from rat small intestine. Appendix: Crystallographic data for a group specific protease from rat intestine

Biochemistry ◽  
1978 ◽  
Vol 17 (5) ◽  
pp. 811-819 ◽  
Author(s):  
Richard G. Woodbury ◽  
Nobuhiko Katunuma ◽  
Keiko Kobayashi ◽  
Koiti Titani ◽  
Hans Neurath ◽  
...  
Keyword(s):  
Small Intestine ◽  
Crystallographic Data ◽  
Rat Small Intestine ◽  
Rat Intestine ◽  
Covalent Structure ◽  
Specific Protease

Release of Dipeptide Hydrolase Activities from Rat Small Intestine Perfused in Vitro and in Vivo

1979 ◽  
Vol 57 (6) ◽  
pp. 529-534 ◽  
Author(s):  
M. L. G. Gardner ◽  
Jane A. Plumb
Keyword(s):  
Small Intestine ◽  
Physiological Significance ◽  
Peptide Transport ◽  
Rat Small Intestine ◽  
Experimental Procedure ◽  
Specific Process ◽  
Whole Cells ◽  
Anaesthetized Rats

1. Hydrolase activities against three dipeptides were measured in mucosal cytoplasm in unperfused intestines and in mucosal cytoplasm, luminal effluents and serosal secretions after perfusion in vitro and in vivo for 1 h. Intestines in vitro were prepared both from anaesthetized rats and from freshly killed rats. 2. Only 0·6–1·9% of the initial cytoplasmic activity was recovered in the luminal effluent when intestines in vitro were prepared from anaesthetized rats. Recoveries in luminal effluents were similar (1·3–3·3%) during perfusion in vivo. 3. Losses of dipeptidases into the luminal effluent were four to eight times greater when intestines in vitro were prepared from freshly killed animals. 4. Similar losses of dipeptidases into the secretion on to the serosal surface were observed; they too were much greater when intestines were prepared from freshly killed animals. 5. Small losses of mucosal DNA during perfusion were also observed; however, losses of cytoplasmic peptidases were consistently slightly greater. 6. Enzyme loss therefore probably occurs both by sloughing of whole cells and by a more specific process which is greatly influenced by experimental procedure. Caution is necessary in the interpretation of peptide transport experiments in vitro, although the possibility that intraluminal hydrolysis is of physiological significance must not be excluded.

scholarly journals The assay and partial characterization of macromolecular heparin depolymerase activity in rat small intestine

1979 ◽  
Vol 180 (3) ◽  
pp. 587-596 ◽  
Author(s):  
E Young ◽  
A A Horner
Keyword(s):  
Small Intestine ◽  
Total Radioactivity ◽  
Gel Chromatography ◽  
Rat Small Intestine ◽  
Ph Optimum ◽  
Tris Maleate ◽  
Two Peaks ◽  
And Storage ◽  
Second Peak

Homogenates of rat small intestine can depolymerize macromolecular rat skin heparin (RS heparin) to products similar in size to commercial heparin [Horner (1972) Proc. Natl. Acad. Sci. U.S.A. 69, 3469–3473]. This activity is attributed to an enzyme provisionally named ‘macromolecular heparin depolymerase’. An assay for macromolecular heparin depolymerase activity in rat small intestine has been developed, based on the action of the enzyme on 35S-labelled macromolecular RS heparin. The depolymerized products are separated into two peaks by gel chromatography through columns of Bio-Gel A-15m. The amount of label in the second peak, expressed as a percentage of the total radioactivity, is the index of enzyme activity. The pH optimum was found to be 6.0 and the temperature optimum 45 degrees C. The enzyme was shown to be most stable in 50mM-Tris/maleate buffer containing 1 mM-EDTA. Macromolecular heparin depolymerase activity measured as a function of time and substrate concentration produced curves typical of an enzymic reaction. Evidence was obtained demonstrating that the activity did not originate from bacteria in the intestine. Macromolecular heparin depolymerase activity was increased by dilution and storage at 7 degrees C for 24 h. This suggests that homogenates of rat small intestine contain an unstable inhibitor of the enzyme.

POSSIBILITY OF ORALLY ADMINISTERED L-LYSINE-A-OXIDASE INTERNALIZATION IN THE MODEL OF ISOLATED CUT OF RAT SMALL INTESTINE

2019 ◽  
Vol 65 (3) ◽  
pp. 463-466
Author(s):  
Gulalek Babaeva ◽  
Yelena Lukasheva ◽  
Zhanneta Cherkasova ◽  
Yelena Treshchalina ◽  
Natalya Andronova ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Small Intestine ◽  
Incubation Medium ◽  
Rat Small Intestine ◽  
Administration Route ◽  
Rat Intestine ◽  
Antitumor Effects ◽  
Luminescence Method ◽  
Parenteral Dose ◽  
Oral Therapeutic

Enzyme L-lysine а-oxidase (LO) exhibits significant antitumor effects by parenteral administration and is promising for clinical trials, particularly in the case of colorectal cancer. The fungi Trichoderma cf.aureoviride Rifai VKM F-4268D is a source of LO. Since there is evidence in the literature of oral use of proteins for therapeutic purposes, it seemed promising to investigate the possibility of such administration route for LO. The goal of the work was to determine the ability of LO to be internalized by the rat small intestine. LO was labeled by Ac-ridinium (LO-Acridinium). Experiments were performed on the rat model using isolated inverted segments of small intestine. The inverted segments were immersed into incubation medium, containing LO-Acridinium. After 30 minutes the samples were taken from the incubation medium and from the intestine segments and relative luminescence was determined by standard flash luminescence method. The amount of absorbed LO-Ac-ridinium was estimated to be 11% for the entire length of the small rat intestine. Based on the optimal total parenteral dose of 400 U/kg for mice the total dose when administered orally was estimated as 4000 U/kg. The absorption of LO through the wall of the rat small intestine was quantitatively characterized, the possibility of its oral administration was proved, and the oral therapeutic dose for mice was estimated.

Partial Characterization and Cellular Localization of Two Deoxyribonucleases in the Small Intestine of the Rat

1971 ◽  
Vol 49 (1) ◽  
pp. 38-43 ◽  
Author(s):  
M. W. Liebbrman ◽  
R. J. Sullivan ◽  
K. H. Shull ◽  
H. Liang ◽  
E. Farber
Keyword(s):  
Small Intestine ◽  
Pancreatic Duct ◽  
Cellular Localization ◽  
Deep Layer ◽  
Superficial Layer ◽  
Rat Small Intestine ◽  
Ph Optimum ◽  
Intestinal Crypt ◽  
Deoxyribonuclease I ◽  
Crypt Cells

We have partially characterized and localized two previously reported deoxyribonucleases from the rat small intestine. After separation of the crypt cells and muscle (the deep layer) from the villus cells (the superficial layer), the latter was found to contain a deoxyribonuclease I with a pH optimum around 6, and a molecular weight of 32 000 – 35 000. It was activated by Co2+, Mg2+, and Mn2+. Ligation of the pancreatic duct reduced the activity in intestinal extracts to about one-third of control levels. A deoxyribonuclease II with a pH optimum of 5.3–5.4 was found associated with the continuously dividing intestinal crypt cells. It was inhibited by Mg2+ and activated by EDTA. Ligation of the pancreatic duct was without effect on this enzyme. The deoxyribonuclease I is probably largely extracellular and serves a digestive function while the deoxyribonuclease II probably is related to intracellular DNA metabolism.

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