Lysine is frequently a first- or second-limiting amino acid in poultry diets. Improving the efficiency of lysine use for protein synthesis would effectively lower the lysine requirement and decrease feed costs. Understanding how lysine is degraded and how the degradation is regulated would identify potential molecular targets for interventions to decrease lysine degradation. To better understan...

The accumulation of free lysine in tobacco seed triggers the stimulation of lysine-ketoglutarate reductase, an enzyme that acts in lysine catabolism. The mechanism of lysine-ketoglutarate reductase stimulation was studied in two different systems: (1) developing seeds of wild-type plants in which the low basal lysine-ketoglutarate reductase activity can be stimulated by the exogenous addition o...

Studies of the nutrition of certain lysine requiring mold mutants indicate that L-a-aminoadipic acid (AAA) or a-ketoadipic acid (KAA) are precursors of lysine. For example, Mitchell and Houlahan (1948) found that certain lysine requiring mutants of Neurospora crassa would respond to either lysine or AAA, and Windsor (1951) subsequently demonstrated that f-C'4-a-aminoadipic acid was completely i...

The isolation of several mutant strains blocked in l-lysine degradation has permitted an assessment of the physiological significance of enzymatic reactions related to lysine metabolism in Pseudomonas putida. Additional studies with intact cells involved labeling of metabolic intermediates from radioactive l- or d-lysine, and patterns of enzyme induction in both wild-type and mutant strains. Th...

BACKGROUND Ingested proteins are known to stimulate a rise in insulin and glucagon concentrations. In our effort to explain this effect, we have begun to measure the effect of individual amino acids. OBJECTIVES The objectives were to determine the effect of lysine ingestion on insulin and glucagon concentrations and whether the effect is moderated by glucose ingestion. DESIGN Thirteen healt...

One-hundred-ninety-two weanling pigs from two separate trials, (initial weight 6.0 and 5.6 kg) and 400 growing-finishing pigs (initial weight 17 kg) were fed normal and high lysine corn diets containing four levels of lysine in a 2 X 4 factorial arrangement. Crossbred (Large White X Landrace X Duroc) pigs were used in all experiments. The objectives of the experiments were to (1) compare normal...

Lysine is an important indispensable amino acid, and describing the lysine content of a food or feedstuff provides useful information about nutritional value. However, when a food or feedstuff is subjected to heating the lysine present can be altered to nutritionally unavailable derivatives. These derivatives can revert back to lysine during the acid hydrolysis step used in amino acid analysis ...

Kinetic properties and substrate specificity of the lysine transport system in porcine mammary gland were studied using mammary tissue explants from nine lactating sows. Sodium dependence of lysine uptake was determined by replacing sodium in the medium with choline. Kinetic parameters of lysine uptake were determined using lysine concentrations from 5 microM to 5.12 mM. Competition of lysine u...

Studies of the nutrition of certain lysine requiring mold mutants indicate that L-a-aminoadipic acid (AAA) or a-ketoadipic acid (KAA) are precursors of lysine. For example, Mitchell and Houlahan (1948) found that certain lysine requiring mutants of Neurospora crassa would respond to either lysine or AAA, and Windsor (1951) subsequently demonstrated that f-C'4-a-aminoadipic acid was completely i...

The study of the tryptic digestion of poly-L-lysine (Katchalski, 1951; Waley & Watson, 1953) has shown that lysine oligopeptides appear duringthe reaction. A better understanding of the mode of action of trypsin on the high-molecular-weight peptide might be gained by a study of the action of the enzyme on a homologous series of lysine peptides (for a preliminary note see Katchalski, Berger & Le...