384 Synthesis of glycine from trans-4-hydroxy-L-proline by placentae but not endometria of gestating gilts

作者：E. Connolly, Wenliang He, Arianna Lopez, Maddison Olivarez, Joseph C. Cain, Carli Lefevre, Alex Ross, Gregory A. Johnson, Fuller W. Bazer, Guoyao Wu · 发表于：Journal of Animal Science · 年份：2024 · DOI：10.1093/jas/skae234.286 · 研究领域：Protein Hydrolysis and Bioactive Peptides

Abstract Trans-4-hydroxy-L-proline (Hyp) is an abundant amino acid in the collagen of pigs. The turnover of this protein releases a large amount of Hyp, traditionally considered a metabolic waste. However, results of recent studies documented the conversion of Hyp into glycine in young pigs. Because pregnant gilts are typically fed a soybean meal-based diet that contains insufficient glycine and provides only 35% of the total glycine needed by pregnant gilts, it is possible that the conceptus can form glycine from Hyp. This hypothesis was tested in the present study. Gilts were fed a 1.8-kg corn- and soybean meal-based diet containing 14% crude protein. On d 90 of gestation, gilts (n = 5) were hysterectomized after euthanasia. Slices (~ 100 mg) of placentae or endometria were incubated at 37 °C for 2 h in oxygenated (95% O2/5% CO2) Krebs-Henseleit bicarbonate buffer (pH 7.4, with 5 mM D-glucose) containing 0 or 2 mM Hyp. After a period of 2 h incubation, 200 μL of 1.5 M HClO4 was added into the incubation medium to stop the reaction. The tissues were homogenized and rinsed with 1 mL water, followed by the addition of 100 μL of 2 M K2CO3. The neutralized extract was analyzed for amino acids using HPLC involving derivatization with o-phthaldialdehyde. Tissues that received no incubation time were determined as well. Data were analyzed by the paired t-test. Results indicated that glycine was produced from 2 mM Hyp by the placenta (Table 1). Glycine was subsequently converted int...