Phosphate metabolism in Methanobacterium thermoautotrophicum (strain ›dH)

The synthesis of different tools to study protease activities are presented. Irreversible inhibitors of the proteasome or cathepsins were equipped with reporter groups and other functionalities to generate probes to study these proteases under different conditions. A two step labeling strategy allowed labeling of all proteasome subunits in living cells, and visualizing these activities after cell lysis. This strategy was employed further to visualize the subunit specificity of a newly developed proteasome inhibitor. An isotope coded tag was introduced in a cathepsin inhibitor in order to assess relative cathepsin activities. An crosslinking functionality or cell penetrating peptide sequence allowed active transport of cathepsin probes into cells, thereby shining a light on the uptake mechanism

Pectic Esterases

Discussed are the pectin esterases. They comprise enzymes that hydrolyze the esters present in the pectin backbone. Currently three classes of esterases have been identified: the pectin methylesterases, the pectin acetylesterases and the rhamnogalacturonan acetylesterase

Pectic Esterases

Discussed are the pectin esterases. They comprise enzymes that hydrolyze the esters present in the pectin backbone. Currently three classes of esterases have been identified: the pectin methylesterases, the pectin acetylesterases and the rhamnogalacturonan acetylesterase

Mode of action of Fusarium moniliforme endopolygalacturonase towards acetylated pectin.

Endopolygalacturonase from Fusarium moniliforme was used to degrade acetylated homogalacturonan previously prepared from sugar beet pulp. The initial velocity and the final percentage of hydrolysis decreased-very rapidly with increasing degree of acetylation, showing that acetyl substitution markedly affected the enzymatic activity. MALDI-TOF mass spectrometry was used to analyse the reaction products and to show acetyl groups on the oligogalacturonates. The results demonstrated that the enzyme was able to accommodate acetyl groups in its active site cleft. The influence of acetyl groups on the mode of action of the enzyme was discussed and compared to the influence of methyl groups. (C) 2003 Elsevier Science Ltd. All rights reserved