The curve for decay of 14C in rat liver protein labelled by injection of NaH14CO3 was analysed to obtain the average turnover rate of mixed liver protein. Three different methods of analysis were used. (1) Unlike decay curves from homogeneous proteins, the curve did not fit a single exponential, but a good fit was obtained with three exponentials. By assuming that the mixture contained three ma...

Protein homeostasis, proteostasis, is essential to understand cell function. Protein degradation is a crucial component of the proteostatic mechanisms of the cell. Experiments on protein degradation are nowadays present in many investigations in the field of molecular and cell biology. In the present paper, we focus on the different experimental approaches to study protein degradation and prese...

The ubiquitin-proteasome system regulates protein degradation in every eukaryotic cell. Recent work has shown that protein turnover mediated by the ubiquitin-proteasome system plays a key role in synaptic plasticity.

Current ruminant feeding systems depend on knowledge of the composition of feeds and the rate and extent of degradation of feed organic matter (OM) and crude protein (CP) in the rumen. The effect of storage and preparation of samples on in vitro gas production and fermentation characteristics of two common forage species, namely alfalfa and ryegrass werestudied. Samples were prepared as fresh (...

The steady-state level of protein in the whole body or in individual tissues is governed not only by the rate of synthesis but by the rate of degradation. Thus protein turnover is a composite term that relates the synthetic and degradative processes. We now have a detailed knowledge of the machinery for synthesizing polypeptide chains and of the requirement for energy to drive the operation, an...

Continuous turnover of intracellular proteins is essential for the maintenance of cellular homeostasis and for the regulation of multiple cellular functions. The first reports showing a decrease in total rates of protein degradation with age are dated more than 50 years ago, when the major players in protein degradation where still to be discovered. The current advances in the molecular charact...