Some characteristics of the alanine aminotransferase- and arginase-inactivating system of lysosomes

Intracellular protein degradation: From a vague idea through the lysosome and the ubiquitin–proteasome system and onto human diseases and drug targeting

“…16 According to a different model, selectivity was determined by the binding affinity of the different proteins to the lysosomal membrane which controls their entry rates into the lysosome and subsequently their degradation rates. 17 For a selected group of proteins, such as the gluconeogenetic enzymes phosphoenol-pyruvate carboxykinase (PEPCK) and fructose-1,6-biphosphatase, it was suggested, though not firmly substantiated, that their degradation in the yeast vacuole was regulated by glucose via a mechanism called "catabolite inactivation" that possibly involves their phosphorylation.…”

Intracellular Protein Degradation: From a Vague Idea through the Lysosome and the Ubiquitin-Proteasome System and onto Human Diseases and Drug Targeting

“…Thus, according to one model, it was proposed that different proteins have different sensitivities to lysosomal proteases, and their half-lives in vivo correlate with their sensitivity to the action of lysosomal proteases in vitro [15] . To explain an extremely long half-life of a protein that was nevertheless sensitive to lysosomal proteases, or alterations in the stability of a single protein under various physiological states, it was suggested that although all cellular proteins are engulfed into the lysosome, only the short-lived proteins are degraded, whereas the long-lived proteins exit back into the cytosol: 'To account for differences in half-life among cell components or of a single component in various physiological states, it was necessary to include in the model the possibility of an exit of native components back to the extralysosomal compartment' [16] . According to a different model, selectivity was determined by the binding affinity of the different proteins to the lysosomal membrane which controls their entry rates into the lysosome, and subsequently their degradation rates [17] .…”

Intracellular protein degradation: from a vague idea thru the lysosome and the ubiquitin–proteasome system and onto human diseases and drug targeting

“…16 According to a different model, selectivity is determined by the binding affinity of the different proteins for the lysosomal membrane, which controls their entry rates into the lysosome, and subsequently their degradation rates. 17 For a selected group of proteins, such as the gluconeogenetic enzymes phosphoenol-pyruvate carboxykinase (PEPCK) and fructose-1,6-biphosphatase, it was suggested, though not firmly substantiated, that their degradation in the yeast vacuole is regulated by glucose via a mechanism called 'catabolite inactivation' that possibly involves their phosphorylation.…”