Crystalline Threonine Research Articles

Effects of increasing crystalline lysine with other amino acids on growth performance of 85- to 135-lb gilts (2003)

A total of 1,134 gilts (each initially 85 lb, PIC L337 x C22) was used in a 28-d experiment to evaluate the effects of replacing soybean meal with up to 8 lb/ton of crystalline Llysine HCl with other crystalline amino acids on growth performance. Gilts were randomly allotted to one of six experimental diets. Diets were corn-soybean meal-based with 3% added fat. Diets included a negative control containing 3 lb/ton of L-lysine HCl and formulated to 0.90% true ileal digestible lysine. Two additional diets were formulated with 3 lb/ton Llysine to 1.0% true ileal digestible lysine but with or without crystalline threonine and methionine to compare threonine to lysine ratios of 60 versus 65% and methionine & cystine (TSAA) ratios of 55 vs. 60%. The three remaining diets contained 6, 7, or 8 lb/ton of Llysine HCl with crystalline threonine and methionine to provide the same ratios relative to lysine of 65 and 60%, respectively.

A note on absorption of crystalline threonine in pigs

A note on absorption of crystalline threonine in pigs

Performance of White- and Brown-Egg Pullets Fed Varying Levels of Diet Protein with Constant Sulfur Amino Acids, Lysine, and Tryptophan

Two experiments were conducted with either white or brown egg pullets to observe their growth and development when fed low protein diets supplemented to normal calculated levels of methionine, methionine + cystine, lysine, and tryptophan. Regardless of diet energy level, pullets were smaller in weight and stature when the protein level declined. This weight differential was maintained through a full laying cycle, during which there was a clear trend of smaller weight birds producing smaller eggs. Egg production and other egg characteristics were unaffected by protein levels in the growing diet. It is possible that the reduction in crude protein level of pullet grower diets will be controlled by the economics of using crystalline threonine.

Threonine aldolase from Candida humicola: II. Purification, crystallization and properties

A procedure is described for the preparation of crystalline threonine aldolase ( l-threonine acetaldehyde-lyase, EC 4.1.2.5) from cells of Candida humicola grown in a synthetic medium containing l-threonine as the sole carbon source. The crystalline enzyme preparation appears homogeneous under ultracentrifugation and acrylamide gel electrophoresis. The molecular weight was determined as 277 000. Pyridoxal phosphate was shown to be associated with the crystalline enzyme. The enzyme has two absorption maxima at 280 and 420 nm. Treatment with cysteine results in a decrease in absorption at 420 nm and a concomitant loss in enzyme activity. The treated, inactive enzyme preparation can be restored to full activity by the addition of pyridoxal phosphate. The amount of pyridoxal phosphate bound to the enzyme was determined by equilibrium dialysis as 6 moles per mole of enzyme.

Crystalline threonine aldolase from Candida humicola

The preparation of crystalline threonine aldolase from the cell extract of Candida humicola is described. The enzyme is homogeneous upon ultracentrifugation and disc electrophoresis. The molecular weight is 277,000. The enzyme exhibits an absorption maximum at 420 mμ, and contains 6 moles of pyridoxal phosphate per mole of enzyme. The enzyme catalyzes the stoichiometric conversion of L-threonine into acetaldehyde and glycine. The enzyme also catalyzes the glycine formation from D, L-allothreonine and L-serine.