Es wurden chemisch definierte einfache Nährmedien für Zellkulturen entwickelt, die das Substrat für das jeweils zu untersuchende Enzym-System enthalten. Der Ablauf der Reaktion wird im Gewebekultur-Überstand bestimmt. Es wurde keine Linearität zwischen dem Proteingehalt der Nährflüssigkeit und dem Abbau des Substrats gefunden, wenn kein erheblicher Zerfall der Zellen vorhanden war. Dies spricht...

This paper reports the use of microfluidic networks (muFNs) to both prepare peptide microarrays and carry out label-free enzyme assays on self-assembled monolayers (SAMs) of alkanethiolates on gold. A poly(dimethylsiloxane) (PDMS) stamp fabricated with microchannels is used to immobilize a linear array of cysteine-terminated peptides onto SAMs presenting maleimide groups. The stamp is then reap...

BACKGROUND Paraoxonase (PON1) enzymatic activity assays are used to characterize sensitivity to organophosphates and oxidative stress. Length of sample storage, temperature and other factors may influence variability of PON1 measurements, especially in longitudinal studies. METHODS Effects of assay temperature, storage duration up to 7 y (-80 degrees C), freeze-thaw cycles, the type of specim...

The performance of two commercially available high-speed photometers, designed for through-the-plate reading, was evaluated. Linearity of instrumental reading and reproducibility of same-day and 2-day measurements were assessed by least-squares analysis and analysis of variance, respectively. For both instruments, the photometric error was on the order of thousandths of an absorbance unit and w...