ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Measurement of the glycogen synthetic pathway in permeabilized cells of cyanobacteria (2001)

Gómez Casati, Diego F. ; Aon, Miguel A. ; Cortassa, Sonia ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

FEMS microbiology letters 194 (2001), S. 0

add to mindlist on the mindlist

Details

ISSN: 1574-6968

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: A simple, rapid and reliable procedure for permeabilizing cyanobacterial cells and measuring the glycogen synthetic pathway in situ, is presented. Cells from Anabaena sp. strain PCC 7120 were permeabilized with a mixture of toluene:ethanol (1:4 v/v). Fluorescence microscopy of cells incubated with fluorescein diacetate showed Anabaena non-permeabilized cells as green fluorescents, whereas permeabilized (viable) cells exhibited the intrinsic red fluorescence. Labelled α-1,4-glucan was recovered when permeabilized cells were incubated with the substrates of ADP-glucose pyrophosphorylase or glycogen synthase. The kinetic and regulatory properties of both enzymes could be reproduced in situ. The simplicity of the procedure and the ability to measure in situ glucan fluxes show the methodology as useful for studying the intracellular regulation of storage polysaccharides in a photosynthetic prokaryote.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1574-6968.2001.tb09438.x

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Effect of phospholipids on the activity of sialosyl lactosylceramide (GM3): N-acetylgalactosaminyl transferase from chick embryo brain (1989)

Cortassa, Sonia ; Maccioni, Hugo J. F.

Springer

Molecular and cellular biochemistry 85 (1989), S. 9-17

add to mindlist on the mindlist

Details

ISSN: 1573-4919

Keywords: gangliosides ; ganglioside galactosaminyltransferase ; phospholipids and galactosaminyltransferase regulation

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: Summary A preparation of UDP-Ga1NAc:sialosyl lactosylceramide N-acetylgalactosaminyl transferase (E.C. 2.4.1.92) obtained from 14-day chick embryo brain was delipidated partially by treatment with cold acetone in the presence of varying amounts of sodium dodecyl sulphate (SDS). The lipid content and the enzyme activity of the preparation decreased as the concentration of SDS increased. At 0.3% SDS the lipid content was about 30% and the enzyme activity about 15% of the original. The activity could be restored up to 60% of the original by added phospholipids, provided the removal of endogenous lipids did not exceed 70%. Phospholipids with diferent composition showed different abilities to restore the enzyme activity. Among phosphatidylcholines the decreasing order of effectivity was dilauroyl → dimiristoyl → dipalmitoyl → distearoyl-choline. Dimiristoyl phosphatidylcholine, dimiristoyl phosphatidylglycerol and dipalmitoyl phosphatidylglycerol activated the enzyme more effectively than dimiristoyl phosphatidyl ethanolamine, dimiristoyl phosphatidic acid or brain phosphatidylserine. No correlation was found between the activating ability and the charge in the polar head group of the lipid added. Addition of dilauroyl phosphatidylcholine to the delipidated preparation increased about 5-fold the Vmax without affecting the apparent Km for both the donor nucleotide and acceptor glycolipid. The data suggest that the lipid composition of the enzyme environment constitutes a potential level of regulation of the activity of this key enzyme of ganglioside biosynthesis.