Glutamic acid hydrochloride

S,4S)-4-(2,2-Diphenylethvl(glutamic Acid Hydrochloride [(2S,4S)-2-Ammo-4-(2,2-diphenylethyl)-pentanedioic Acid Hydrochloride, 61] [951... 

The wet gluten (about 1300 g. ) is placed (Note 3) in a 5-I. round-bottom flask and covered with 1600 cc. of concentrated hydrochloric acid (sp. gr. 1.19). This reaction mixture is then warmed on the steam bath until the purple color disappears (about two hours). A reflux condenser is then attached and the solution is boiled gently over a flame for about eighteen hours. The hot solution is filtered with suction (Note 4) and the black residue of melanin is washed with about 200 cc. of water. The combined filtrate and washings are concentrated under reduced pressure until the volume is reduced to about 1500 cc. This solution is allowed to cool to room temperature and the crystals of glutamic acid hydrochloride filtered and washed with two 30-cc. portions of 95 per cent ethyl alcohol saturated with hydrogen chloride. The washings are discarded (Note 5) and the... 

The yield of glutamic acid hydrochloride varies somewhat with the brand of flour. The results described in this procedure were obtained with Gold Medal flour. 

If gluten flour (40 per cent gluten) is used instead of ordinary flour, the procedure is approximately the same. A 5-lb. sack of gluten flour is washed to remove the starch. The wet gluten is placed in a 6-1. Pyrex flask with 3500 cc. of concentrated hydrochloric acid (sp. gr. 1.19) and the hydrolysis is carried out as described above. After the hydrolysis and removal of the melanin by filtration, the solution is concentrated to about 1300 cc. The glutamic acid hydrochloride is then precipitated as already described. After two recrystallizations, the yield is 180-190 g. From the mother liquors a further yield of 45-50 g, is obtained, making a total of 225-230 g. 

Glidine, a commercial diabetic food which is prepared from wheat flour and contains over go per cent of protein, may be used as a satisfactory source of glutamic acid. If this is used, it is not necessary to wash in order to remove the starch. From 1130 g. of this material, by hydrolyzing with 2500 cc. of concentrated hydrochloric acid and working up as before, 275-285 g. of glutamic acid hydrochloride may be obtained. Usually, the product from glidine is more difficult to decolorize. It has been found that an ether extraction of the hydrolysis mixture, after removal of the melanin, improves the color of the final product. 

Glutamic acid has been prepared from the hydrochloride by treating a water solution with strong alkalies,2 alkali carbonates,3 and ammonium hydroxide.4 Hopkins 5 has shown that the addition of 6-8 volumes of alcohol to a concentrated water solution of glutamic acid hydrochloride will cause a slow precipitation of the free amino acid. 

Fig. 3-3 Titration of 10 mmol glutamic acid hydrochloride by NaOH.

L-Glutamic Acid Hydrochloride occurs as a white, crystalline powder. One gram dissolves in about 3 mL of water. It is almost insoluble in alcohol and in ether. Its solutions are acid to litmus. 

Figure 5-1 Titration of glutamic acid hydrochloride with base, showing possible ionic states of the amino acid as a function of pH.

DLGLAC. D,L-Glutamic acid hydrochloride (C5H10NO4, Cl-). Dawson B (1953) Acta Crystallogr 6 81... 

B. Dawson. Acta Cryst. 6,81-7 (1953). Grystal structure DL-glutamic acid hydrochloride. 

Acidulin [Lilly], TM for glutamic acid hydrochloride acid value. The number of milligrams of potassium hydroxide required to neutralize the free acids present in 1 g of oil, fat, or wax. The determination is made by titrating the sample in hot 95% ethanol using phenolphthalein as indicator. 

L-glutamic acid hydrochloride, as determined through fits of the static and MAS spectra, done using the DMFIT program. In addition, the authors reconfirmed the values obtained previously for L-tyrosine hydrochloride. While no experimental CSA data were reported, first principles calculations were done, predicting small CS tensor spans ranging between 78 and 157 ppm. ... 

Glutamic acid is also prepared by the acid hydrolysis of gluten. In a procedure described by Waters,43 the crude, hydrolyzed product is filtered while hot to remove the insoluble humus, after which the filtrate is cooled to crystallize the glutamic acid hydrochloride. The crystals are dissolved in water, and sufficient sodium hydroxide is added to neutralize the free hydrochloric acid. The solution (pH 1.5) is heated to 80 to 90° C and decolorized with activated carbon. When the filtrate is cool, sufficient sodium hydroxide is added to raise the pH to 3.2 and the solution is then allowed to stand until crystallization is complete. 

In fennentation of this kind other acids failed to increase the fermentation as did glutamic acid hydrochloride, so we were led to... 

HYDROCHLORIDE a-GLUTAMIC ACID HYDROCHLORIDE GLUTAMNIC ACID HYDROCHLORIDE /-GLUTAMINIC ACID HYDROCHLORIDE... 

L-2-Aminoglutaric acid hydrochloride. See L-Glutamic acid hydrochloride... 

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