Measurement of Free Amino Acids in Plasma and Serum by Means of High-Voltage Paper Electrophoresis

SummaryCheddar cheese was produced free of non-starter bacteria, acidified with starter or glucono-δ-lactone and containing active coagulant (chymosin or pepsin) or inactivated coagulant (pepsin). The level and type of proteolysis in the experimental cheeses was monitored by protein solubility at pH 4·6 and in 12 % TCA, polyacrylamide gel and high voltage paper electrophoresis, gel filtration and paper chromatography. The results show that the coagulant was primarily responsible for the formation of large peptides while small peptides and free amino acids were produced principally by the starter, possibly from coagulant-produced peptides.

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Quantitative Measurement of Individual Free Amino Acids in Urine by Means of High Voltage Paper Electrophoresis. Investigations of a Group of Mentally Retarded Patients

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365516609049046 ◽

1966 ◽

Vol 18 (6) ◽

pp. 629-637 ◽

Cited By ~ 7

Author(s):

P. Juui

Keyword(s):

Amino Acids ◽

High Voltage ◽

Free Amino Acids ◽

Free Amino ◽

Quantitative Measurement ◽

Mentally Retarded ◽

Paper Electrophoresis

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β-Aspartylglycine, a substance unique to caecal contents of germ-free and antibiotic-treated mice

Biochemical Journal ◽

10.1042/bj1750807 ◽

1978 ◽

Vol 175 (3) ◽

pp. 807-812 ◽

Cited By ~ 18

Author(s):

G W Welling ◽

G Groen

Keyword(s):

Amino Acids ◽

High Voltage ◽

Free Amino Acids ◽

Free Amino ◽

Fold Increase ◽

High Concentration ◽

Colour Reaction ◽

Similar Treatment ◽

Gram Negative ◽

Germ Free

The caecal supernatants from germ-free, antibiotic-treated and control mice were compared with respect to their content of low-molecular-weight substances (less than 3500 mol. wt.). The supernatants contained about the same amount of free amino acids. After acid hydrolysis, the caecal supernatants of germ-free and antibiotic-treated mice showed a 2.9-fold increase in free amino acids, whereas a similar treatment of the supernatant from control mice resulted in a 2.6-fold increase. By gel filtration on Sephadex G-25, and high-voltage paper electrophoresis at pH 3.5 of the fractions eluted after the void volume, it was found that the caecal supernatants of germ-free and antibiotic-treated mice contained a substance more acidic than aspartic acid. Preparative high-voltage electrophoresis, dansylation, amino acid analysis and a specific colour reaction showed the substance to be beta-aspartylglycine. After a minimal 36 h of treatment with neomycin and bacitracin, a high concentration of beta-aspartylglycine was found, and no enterococci and aerobic Gram-negative rods could be cultured from the caecal contents. The possibility that in one mouse the appearance of beta-aspartylglycine was related to a decrease in Gram-negative rods was ruled out by selective elimination of aerobic Gram-negative rods by using polymyxin B. This suggests that other bacteria concomitantly eliminated with the enterococci and aerobic Gram-negative rods, directly or indirectly, could play a role in the accumulation of beta-aspartylglycine.

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