New chromogenic substrates for X-prolyl dipeptidyl-aminopeptidase

Nagatsu, Toshiharu; Hino, Masao; Fuyamada, Hiroshi; Hayakawa, Taro; Sakakibara, Shumpei; Nakagawa, Yasuo; Takemoto, Takashi

doi:10.1016/0003-2697(76)90227-x

Cited by 295 publications

(115 citation statements)

References 16 publications

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“…After thawing, the intestinal mucosa was homogenized in cold distilled water (1 g intestinal mucosa/5 ml distilled water) and centrifuged for 5 min at 1000 g at 4 C. The protein content was then determined as described by Hartree (1972), using BSA as the standard. The activities of aminopeptidase A and N were assayed with -glutamylp-nitroanilide and -leucyl-p-nitroanilide as substrates respectively (Maroux et al 1973), and that of dipeptidase IV was assayed with glycyl--prolyl-p-nitroanilide (Nagatsu et al 1976). The resulting enzymatic units (IU) are expressed as µmol p-nitroanilide released/min at 37 C. Lactase, maltase and sucrase were determined as described earlier (Dahlquist 1964) with minor modifications.…”

Section: Brush Border Enzyme Activitymentioning

confidence: 99%

Exogenous leptin controls the development of the small intestine in neonatal piglets

Woliński¹,

Biernat²,

Guilloteau³

et al. 2003

Journal of Endocrinology

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Leptin, a hormone produced and secreted by adipose tissue, muscles and stomach, is involved in the regulation of adipose tissue mass, food intake and body weight in neonatal animals. It is also produced in the mammary glands and secreted into the colostrum and milk. Since leptin receptors are widely distributed in the small intestine mucosa, the aim of the present study was to investigate the effect of exogenous leptin on the development of the small intestine in neonatal piglets. Male neonatal piglets were fed with sow's milk or artificial milk formula. Every 8 h the latter received either vehicle or leptin (2 or 10 µg/kg body weight). The animals were either killed after 6 days of treatment and the small intestine sampled for histology and brush border enzyme activities or were tested for marker molecule (Na-fluorescein and BSA) absorption in vivo. Feeding milk formula slowed the maturation of small intestinal mucosa compared with feeding sow's milk. However, after leptin treatment the length of the small intestine was increased, and intestinal villi length, but not crypt size, was reduced compared with controls. The mitotic index was increased and the percentage of vacuolated enterocytes was reduced in the entire small intestine. Enterocyte brush border protease and lactase activities were reduced in the jejunum. Nafluorescein marker molecule absorption did not change but that of BSA was reduced 3·8-fold. In conclusion, exogenous leptin administered in physiological doses reversed the maturation of the small intestinal mucosa to the range found in sow-reared piglets.

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Section: Brush Border Enzyme Activitymentioning

confidence: 99%

Exogenous leptin controls the development of the small intestine in neonatal piglets

Woliński¹,

Biernat²,

Guilloteau³

et al. 2003

Journal of Endocrinology

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“…ODC activity was calculated from the difference between 14 CO 2 production in the absence or presence of 10 mm DFMO known to totally inhibit ODC activity [19]. DPP IV activity was measured using the method of Nagatsu et al [20] in sonicated cells recovered from the culture flask with a cell scraper.…”

Section: Ornithine Decarboxylase (Odc) and Dipeptidylpeptidase IV (Dpmentioning

confidence: 99%

Butyrate metabolism upstream and downstream acetyl‐CoA synthesis and growth control of human colon carcinoma cells

Leschelle¹,

Delpal²,

Goubern

et al. 2000

European Journal of Biochemistry

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Butyrate is a short chain fatty acid (SCFA) produced by bacterial fermentation of dietary fibers in the colon lumen which severely affects the proliferation of colon cancer cells in in vitro experiments. Although butyrate is able to interfere with numerous cellular targets including cell cycle regulator expression, little is known about butyrate metabolism and its possible involvement in its effect upon colon carcinoma cell growth. In this study, we found that HT-29 Glc 2/1 cells strongly accumulated and oxidized sodium butyrate without producing ketone bodies, nor modifying oxygen consumption nor mitochondrial ATP synthesis. HT-29 cells accumulated and oxidized sodium acetate at a higher level than butyrate. However, sodium butyrate, but not sodium acetate, reduced cell growth and increased the expression of the cell cycle effector cyclin D3 and the inhibitor of the G1/S cdk-cyclin complexes p21/WAF1/Cip1, demonstrating that butyrate metabolism downstream of acetyl-CoA synthesis is not required for the growth-restraining effect of this SCFA. Furthermore, HT-29 cells modestly incorporated the 14 C-labelled carbon from sodium butyrate into cellular triacylglycerols and phospholipids. This incorporation was greatly increased when d-glucose was present in the incubation medium, corresponding to the capacity of hexose to circulate in the pentose phosphate pathway allowing NADPH synthesis required for lipogenesis. Interestingly, when HT-29 cells were cultured in the presence of sodium butyrate, their capacity to incorporate 14 C-labelled sodium butyrate into triacylglycerols and phospholipids was increased more than twofold. In such experimental conditions, HT-29 cells when observed under an electronic microscope, were found to be characterized by an accumulation of lipid droplets in the cytosol. Our data strongly suggest that butyrate acts upon colon carcinoma cells upstream of acetyl-CoA synthesis. In contrast, the metabolism downstream of acetyl-CoA [i.e. oxidation in the tricarboxylic acid (TCA) cycle and lipid synthesis] likely acts as a regulator of butyrate intracellular concentration.Keywords: butyrate; metabolism; growth; colon carcinoma cells.Epidemiological studies generally suggest a protective role of dietary fibers in colon carcinogenesis [1]. Dietary fibers contained in vegetables, fruit and cereals are heterogeneous group of compounds with different physicochemical properties [2]. They escape digestion and are recovered in the colon lumen. The different proposed mechanisms of action in which fibers may protect against colorectal tumours development include the inactivation of carcinogenic substances, an increase in faecal bulk with shortening of the bowel transit time and a decreased contact time [3]. In the large intestine, fibers can undergo anaerobic fermentation by intestinal flora leading to the production of various metabolites including short chain fatty acids (SCFA, mainly acetate, propionate and butyrate). Among these three, butyrate has received much attention due to its ability to severely ...

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“…Dipeptidylpeptidase IV (CD26, EC 3.4.14.5) activity was assayed as described by Nagatsu et al [12]. Calf ADA activity (50 U/ml) was completely abolished after preincubation with 100/.tM HgC12 (2 h) and removal of free Hg 2+ by gel filtration using Sephadex G-25.…”

Section: Enzyme Activities and Ada Inhibition By Hg 2+mentioning

confidence: 99%

Adenosine deaminase affects ligand‐induced signalling by interacting with cell surface adenosine receptors

et al. 1996

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Adenosine deaminase (ADA) is not only a cytosolic enzyme but can be found as an ecto-enzyme. At the plasma membrane, an adenosine deaminase binding protein (CD26, also known as dipeptidylpeptidase IV) has been identified but the functional role of this ADMCD26 complex is unclear. Here by confocal microscopy, affinity chromatography and coprecipitation experiments we show that A 1 adenosine receptor (AIR) is a second ecto-ADA binding protein. Binding of ADA to AtR increased its affinity for the ligand thus suggesting that ADA was needed for an effective coupling between A~R and heterotrimeric G proteins. This was confirmed by the fact that ASA, independently of its catalytic behaviour, enhanced the ligand-induced second messenger production via AtR. These findings demonstrate that, apart from the cleavage of adenosine, a further role of ecto-adenosine deaminase on the cell surface is to facilitate the signal transduction via AIR.

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New chromogenic substrates for X-prolyl dipeptidyl-aminopeptidase

Cited by 295 publications

References 16 publications

Exogenous leptin controls the development of the small intestine in neonatal piglets

Exogenous leptin controls the development of the small intestine in neonatal piglets

Butyrate metabolism upstream and downstream acetyl‐CoA synthesis and growth control of human colon carcinoma cells

Adenosine deaminase affects ligand‐induced signalling by interacting with cell surface adenosine receptors

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