Hydrochloric Acid → Ethyl methioninate

Temperature

90 °C

A solution of 2.2 g of L-lysine in 13.0 ml of ethyl alcohol and 1.6 ml of conc. sulfuric acid was heated under reflux at 90° C. for 5 hours, obtaining L-lysine ethyl ester in a yield of 76.5%. Separately, L-methionine ethyl ester was prepared from 0.8 g of L-methionine in the same manner as in Example 1. After 66 mg of papain and 6.6 mg of L-cysteine were dissolved in a solution of 1.8 g of sodium carbonate and 0.52 g of sodium hydrogen carbonate in 20 ml of water, 20 g of wheat gluten in limited amounts was added to the solution and mixed therewith. The previously prepared reaction solutions of L-lysine and L-methionine ethyl esters were all added to the protein system of wheat gluten, and the system was kept at 37° C. for 24 hours to effect plastein reaction. The rates of incorporation of L-lysine and L-methionine were 62.7% and 81.6%, respectively. At the end of the reaction, the reaction solution was diluted with water to a volume of 300 ml and adjusted to pH 7 with hydrochloric acid before it was subjected to repeated concentration operations for desalting and purification using a reverse osmosis membrane equipped small experimental apparatus (equipped with a DRS-10 flat membrane, manufactured by Daicell Chemical K.K.) under an operating pressure of 15 kg/cm2. The concentrate resulting from the reverse osmosis treatment was again diluted with water to a volume of 400 ml and adjusted to pH 2.0 with phosphoric acid. After 0.4 g of pepsin was added to the solution, the hydrolytic reaction was carried out for 3 hours. Thereafter, 0.4 g of orientase was added and the hydrolytic reaction was continued for an additional 30 hours. The reaction solution was heated to 90° C. for 10 minutes and then centrifuged under 2000G to remove the solids. The supernatant was freeze dried to yield 18.3 g of a low-molecular weight peptide mixture. This product had an average molecular weight of 350 and contained 8.9% of free amino acids, and the gel filtration showed that it contained 86.2% of compounds with a molecular weight of 700 or lower. Table 2 shows the amino acid composition of the starting protein, wheat gluten and the low-molecular weight peptide mixture produced therefrom. As seen from Table 2, the low-molecular weight peptide mixture had the increased contents of L-lysine and L-methionine as compared with the starting protein.

1. additionwas added to the solution
2. additionmixed
3. additionall added to the protein system of wheat gluten
4. customplastein reaction
5. customAt the end of the reaction
6. concentrationwas subjected to repeated concentration operations
7. custompurification
8. customequipped small experimental apparatus (
9. customequipped with a DRS-10 flat membrane
10. customThe concentrate resulting from the reverse osmosis treatment
11. additionAfter 0.4 g of pepsin was added to the solution
12. customthe hydrolytic reaction
13. waitwas carried out for 3 hours
14. additionThereafter, 0.4 g of orientase was added
15. customthe hydrolytic reaction
16. waitwas continued for an additional 30 hours
17. customto remove the solids
18. customdried

ORD record

ord-aad5a28f74fa42309cf014471f615119

Source dataset

uspto-grants-1990_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04940662