Biochemical characteristics and subcellular localizations of rat liver neuraminidase isozymes: A paradox resolved

Samollow, Paul B.; Ford, Allen L.; VandeBerg, John L.

doi:10.1007/bf02401418

Cited by 4 publications

(3 citation statements)

References 28 publications

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“…Because OF did not show N-acetyl-neuraminidase and a-Dgalactosidase activities at pH 7.2, a small trial was run to assay these two enzymes at acidic pH. Acidic neuraminidase and a-Dgalactosidase of lysosomal origin have an optimum pH of 4.6-4.8 (Samollow et al 1990) and 4.4 (Ohshima et al 1997) respectively. Therefore, the enzymatic assays for samples, blanks, and controls were done, as described previously, but using a sodium acetateacetic acid (0.2 M), adjusted to pH 4.4 as the assay buffer.…”

Section: Assays For Glycosidasesmentioning

confidence: 99%

Determination of glycosidase activity in porcine oviductal fluid at the different phases of the estrous cycle

Carrasco

Romar

Sánchez³

et al. 2008

Reproduction

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Sperm-oocyte binding and gamete-oviductal epithelium interactions are carbohydrate-mediated events occurring in the oviductal fluid (OF). Thus, knowledge about the activities of glycosidases (enzymes catalyzing hydrolytic cleavage of terminal sugar residues) in this milieu would help us understand the molecular mechanisms involved in these events. This work was carried out to investigate the glycosidase activity, protein content, and volume of OF collected from gilts and sows. Oviducts were classified into four phases of the estrous cycle (early follicular, late follicular, early luteal, and late luteal) based on the appearance of the ovaries. OF was aspirated, centrifuged, measured for volume, and frozen until assay. Substrates conjugated to 4-methylumbelliferyl were used to screen the activities of seven different glycosidases at physiological pH (7.2). a-L-Fucosidase and b-N-acetyl-glucosaminidase activities increased at the late follicular phase to decrease after ovulation. b-D-Galactosidase, a-D-mannosidase, and b-N-acetyl-galactosaminidase showed higher activities at the early follicular phase, which decreased after ovulation. N-Acetyl-neuraminidase and a-D-galactosidase did not show activity at any phase of estrous cycle neither in sows nor in gilts at pH 7.2, although it did at acidic pH (4.4) in the follicular and luteal phase samples. Total protein also changed during the cycle showing the maximum secretion at the late follicular phase (2118.6G200.7 mg/oviduct). The highest volumes of OF were collected from the oviducts at the late follicular phase (50.7G1.3 ml/oviduct). These results indicate that OF from sows and gilts shows glycosidase activity varying throughout the estrous cycle suggesting a role of these enzymes in carbohydrate-mediated events. Reproduction (2008) 136 833-842

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Section: Assays For Glycosidasesmentioning

confidence: 99%

Determination of glycosidase activity in porcine oviductal fluid at the different phases of the estrous cycle

Carrasco

Romar

Sánchez³

et al. 2008

Reproduction

View full text Add to dashboard Cite

show abstract

“…Because bOF did not show N-acetyl-neuraminidase and α-dgalactosidase activity at pH 7.2, a small trial was run to assay the activity of these two enzymes at acidic pH. Acidic neuraminidase and α-d-galactosidase of lysosomal origin have an optimum pH of 4.6-4.8 (Samollow et al 1990) and 4.4 (Ohshima et al 1997), respectively. So, the enzymatic assays for samples, blanks and controls were run as before, but using sodium acetate-acetic acid (0.2 m) adjusted to pH 4.4 as the assay buffer.…”

Section: Glycosidase Assaysmentioning

confidence: 99%

Glycosidase determination in bovine oviducal fluid at the follicular and luteal phases of the oestrous cycle

Carrasco

Coy

Sánchez

et al. 2008

Reprod. Fertil. Dev.

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Gamete recognition and binding of spermatozoa to the oviduct are carbohydrate-mediated processes in which several glycosidases are thought to have a role, although this has not been demonstrated unequivocally. Oviducal fluid is the biological milieu in which fertilisation and early embryo development take place, but the enzyme composition of oviducal fluid is largely unknown. The aim of the present study was to determine glycosidase activity and protein content in bovine oviducal fluid (bOF) and the volume of fluid collected per oviduct. Oviducts obtained from a slaughterhouse were classified as either in the follicular or luteal phase on the basis of ovarian luteal morphology. Oviducal fluid was aspirated, centrifuged and the volume determined. Samples were then frozen until assay. Substrates conjugated to 4-methylumbelliferyl were used to screen for the activity of seven glycosidases at pH 7.2. The results indicate that bOF has alpha-l-fucosidase, beta-N-acetyl-glucosaminidase, beta-d-galactosidase, alpha-D-mannosidase and beta-N-acetyl-galactosaminidase activity during both phases of the cycle, with the specific activity of the latter two enzymes being higher during the follicular phase. There was no N-acetyl-neuraminidase or alpha-d-galactosidase activity detected in bOF at either phase of the oestrous cycle at pH 7.2, but activity for both glycosidases was detected at pH 4.4. There were no differences in protein concentration or the volume of bOF collected between the two phases of the cycle. These findings indicate that oviducal fluid exhibits glycosidase activity, with specific variations throughout the oestrous cycle, suggesting that these enzymes play a role in carbohydrate-mediated events.

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“…The de-sialylation of ApoB48 could be the main atherogenic factor [ 7 , 9 , 10 , 11 , 12 ]. The trans-sialidase activity was found in human blood plasma [ 11 , 12 , 13 , 14 ]. However, the sialidase in the blood that was supposed to cause LDL desialylation was not cloned.…”

Section: Introductionmentioning

confidence: 99%

Role of Endothelial Regeneration and Overloading of Enterocytes with Lipids in Capturing of Lipoproteins by Basement Membrane of Rat Aortic Endothelium

et al. 2022

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Atherosclerosis is a complex non-monogenic disease related to endothelial damage in elastic-type arteries and incorrect feeding. Here, using cryodamage of endothelial cells (ECs) of rat abdominal aorta, we examined the role of the EC basement membrane (BM) for re-endothelization endothelial regeneration and its ability to capture low density lipoproteins (LDLs). Regeneration of endothelium induced thickening of the ECBM. Secretion of the BM components occurred in the G2-phase. Multiple regenerations, as well as arterial hypertension and aging, also led to the thickening of the BM. Under these conditions, the speed of re-endothelialization increased. The thick BM captured more LDLs. LDLs formed after overloading of rats with lipids acquired higher affinity to the BM, presumably due to the prolonged transport of chylomicrons through neuraminidase-positive endo-lysosomes. These data provide new molecular and cellular mechanisms of atherogenesis.

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Biochemical characteristics and subcellular localizations of rat liver neuraminidase isozymes: A paradox resolved

Cited by 4 publications

References 28 publications

Determination of glycosidase activity in porcine oviductal fluid at the different phases of the estrous cycle

Determination of glycosidase activity in porcine oviductal fluid at the different phases of the estrous cycle

Glycosidase determination in bovine oviducal fluid at the follicular and luteal phases of the oestrous cycle

Role of Endothelial Regeneration and Overloading of Enterocytes with Lipids in Capturing of Lipoproteins by Basement Membrane of Rat Aortic Endothelium

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