ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

On the involvement of a glucose 6-phosphate transport system in the function of microsomal glucose 6-phosphatase (1975)

Arion, William J. ; Wallin, Bruce K. ; Lange, Alex J. ; [et al.]

Springer

Molecular and cellular biochemistry 6 (1975), S. 75-83

add to mindlist on the mindlist

Details

ISSN: 1573-4919

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: Summary A model for microsomal glucose 6-phosphatase (EC 3.1.3.9) is presented. Glucose 6-phosphatase is postulated to be resultant of the coupling of two components of the microsomal membrane: 1) a glucose 6-phosphate — specific transport system which functions to shuttle the sugar phosphate from the cytoplasm to the lumen of the endoplasmic reticulum; and 2) a catalytic component, glucose-6-P phosphohydrolase, bound to the luminal surface of the membrane. A large body of existing data was shown to be consistent with this hypothesis. In particular, the model reconciles well-documented differences in the kinetic properties of the enzyme of untreated and modified microsomal preparations. Characteristic responses of the enzyme to changes in nutritional and hormonal states may be attributed to adaptations which alter the relative capacities of the transport and catalytic components.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01732001

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

A critical evaluation of the use of filipin-permeabilized rat hepatocytes to study functions of the endoplasmic reticulum in situ (1987)

McEwen, Bruce F. ; Telford, John N. ; Handelman, Caryl T. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Cell Biochemistry and Function 5 (1987), S. 263-272

add to mindlist on the mindlist

Details

ISSN: 0263-6484

Keywords: Filipin ; hepatocytes ; electron microscopy ; endoplasmic reticulum ; cell permeabilization ; glucose-6-phosphatase ; Chemistry ; Biochemistry and Biotechnology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: We have used transmission (TEM) and scanning electron microscopy (SEM) and leakage of lactate dehydrogenase (LDH; EC 1.1.1.27) to evaluate two published procedures which use filipin to render isolated rat hepatocytes permeable to ionic substrates. Cells treated by the procedure of Jorgenson and Nordlie6 retained less than 10 per cent of their LDH. TEM revealed severe damage to the internal structure of these cells, which included swelling, disintegration and extensive vesicularization of the endoplasmic reticulum (ER). Hepatocytes treated with filipin by the procedure of Gankema et al.13 retained 65-75 per cent of their LDH and displayed incomplete but highly variable permeability to Trypan blue. SEM revealed the loss of microvilli, other signs of swelling, and the presence of large lesions in the plasma membrane. TEM revealed signs of cell swelling, but the nuclei and the mitochondria were only moderately altered. The rough ER was not swollen, but significant fragmentation was evident and characteristic stacks of lamellar ER were never seen.We conclude that useful information about the functions of the ER in situ cannot be obtained from studies of filipin-treated cell. Our results indicate that retention of LDH is not a sufficient criterion of preservation of cell morphology and that staining with Trypan blue may significantly underestimate the permeability of cells to small ionic metabolites.

Additional Material: 4 Ill.