Autophagic (lysosomal) and proteasomic protein degradation are important regulatory mechanisms in the homeostasis of muscle mass, that may be profoundly disturbed in cancer and other wasting syndromes. Due to the inhibiting effect of amino acids and insulin, net proteolysis is restricted to the fasted state, and in autophagy certain amino acids have been identified as 'regulatory' in the rat, i...

A large amount of gamma-aminobutyric acid (GABA) was found to accumulate in tomato (Solanum lycopersicum) fruits before the breaker stage. Shortly thereafter, GABA was rapidly catabolized after the breaker stage. We screened the GABA-rich tomato cultivar 'DG03-9' which did not show rapid GABA catabolism after the breaker stage. Although GABA hyperaccumulation and rapid catabolism in fruits is w...

Lysine catabolism in plants is initiated by a bifunctional LKR/SDH (lysine-ketoglutarate reductase/saccharopine dehydrogenase) enzyme encoded by a single LKR/SDH gene. Yet, the AtLKR/SDH gene of Arabidopsis also encodes a second gene product, namely a monofunctional SDH. To elucidate the regulation of lysine catabolism in Arabidopsis through these two gene products of the AtLKR/SDH gene, an ana...

Three patients with bacterial endocarditis who developed renal failure have been studied by means of a radiofibrinogen catabolism study. Two were studied at the time of bacteraemia and one during the subsequent "immunological phase" of circulating immune complexes. Accelerated fibrinogen catabolism was found in all cases. Intravascular coagulation may be an important factor in the pathogenesis ...

SUMMARY Accelerated albumin catabolism without a compensatory increase in anabolism leading to decreased serum albumin concentration in tumor-bearing animals was observed. Supplemental high-protein feedings augmented albumin synthesis, which resulted in a return of serum albumin to normal levels in tumor-bearing rats. Adrenalectomy abolished tumor-induced accelerated albumin catabolism.

During growth on a glucose-tryptone medium, Bacillus subtilis 6051 (Marburg strain) exhibited three phases of isoprene (2-methyl-1, 3-butadiene) formation, corresponding to (i) glucose catabolism and secretion of acetoin, (ii) catabolism of acetoin, and (iii) the early stages of sporulation. These results establish an experimental system for studying the biological role of isoprene formation.

Biologically active concentrations of potently vasoactivc and platelet-active adenine nucleotides are generated in plasma by a variety of pathophysiological mechanisms. Although there is evidence that ATP and ADP are inactivated by endothelial ectonucleotidases, there has been little attempt to study the metabolic routes of their catabolism in blood or to assess the contribution of this process...

The metabolism of the fifth component of complement (C5), and its relatonship to metabolism of the third component of complement (C3), has been studied in normal subjects and patients by simultaneous administration of radioiodine labeled C5 and C3. In seven normal subjects the fractional catabolic rate of C5 ranged from 1.5 to 2.1% of the plasma pool/h and extravascular/intravascular distributi...

BACKGROUND We previously reported an association between tryptophan (Trp) catabolism and immune dysfunction in HIV monoinfection. Coinfection with HIV is associated with more rapid evolution of hepatitis C virus (HCV)-associated liver disease despite antiretroviral therapy (ART), possibly due to immune dysregulation. We hypothesized that liver fibrosis in HIV/HCV coinfection would be associated...