Automated Determination of Free Amino Groups in Serum and Plasma Using 2,4,6-Trinitrobenzene Sulfonate

1969 ◽  
Vol 15 (9) ◽  
pp. 891-901 ◽  
Author(s):  
D W Palmer ◽  
T Peters
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Clinical Applications ◽  
Amino Groups ◽  
Automated Method ◽  
Total Free Amino Acids ◽  
Colored Complexes ◽  
Automated Determination

Abstract A simple automated method is described for determining the level of total free amino acids in the blood. The method utilizes the AutoAnalyzer, and is based on the formation of colored complexes by uniting free amino groups with 2,4,6-trinitrobenzene sulfonate (TNBS). Proteins do not interfere because the free amino acids are first separated by dialysis. Characteristics of the reaction and potential clinical applications of the procedure are discussed.

Determination of free tyrosine in equestrian supplements by LC–MS/MS and comparison of its quantity with total free amino acids content in view of doping control

2019 ◽  
Vol 146 ◽  
pp. 56-65 ◽  
Author(s):  
Emilia Waraksa ◽  
Konrad Kowalski ◽  
Rafał Rola ◽  
Ewa Kłodzińska ◽  
Tomasz Bieńkowski ◽  
...  
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Doping Control ◽  
Total Free Amino Acids

Determination of total free amino acids with o-phthalaldehyde and N-acetyl-l-cysteine

1990 ◽  
Vol 42 (3) ◽  
pp. 288-293 ◽  
Author(s):  
M.J.Medina Hernández ◽  
R.M.Villanueva Camañas ◽  
M.C.García Alvarez-Coque
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Total Free Amino Acids

Measurement of proteolysis in cheese: relationship between phosphotungstic acid-soluble N fraction by Kjeldahl and 2,4,6- trinitrobenzenesulphonic acid-reactive groups in water-soluble N

1994 ◽  
Vol 61 (3) ◽  
pp. 437-440 ◽  
Author(s):  
Yvette Bouton ◽  
Remy Grappin
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Phosphotungstic Acid ◽  
Water Soluble ◽  
Hydroxyl Groups ◽  
Amino Groups ◽  
Reactive Groups ◽  
Primary Amino

Free amino groups produced during cheese ripening are used to indicate the extent of cheese proteolysis. Several studies have shown a high correlation between the level of free amino acids and the flavour of Gouda (Aston et al. 1983) or Comté (Grappin & Berdagué, 1989). Measurement of the level of free amino acids seems useful for the investigation of flavour chemistry in cheese (Lemieux et al. 1990). The determination of N fractions is often used to estimate the degree of proteolysis in cheese, but since this procedure is laborious and time consuming several attempts have been made to replace it by more rapid methods (Ardö & Meisel, 1991). Since its introduction by Satake et al. (1960), the 2,4,6-trinitrobenzenesulphonic acid (TNBS) method has been widely used for the determination of free amino groups. Because TNBS does not react with the imino groups of histidine and proline or the hydroxyl groups of tyrosine, serine or threonine, it has been accepted as a selective reagent for primary amino groups (Burger, 1974). Measurement of N by Kjeldahl in the phosphotungstic acid (PTA)–sulphuric acid extract (Gripon et al. 1975) estimates the N of free amino acids and low molecular mass peptides. The purpose of this study was to compare the TNBS and PTA-soluble N methods in order to find out whether the TNBS procedure can replace that of PTA-soluble N in the determination of a cheese proteolysis index.

scholarly journals A METHOD FOR THE DETERMINATION OF FREE AMINO ACIDS IN RAT ORGANS AND TISSUES

1950 ◽  
Vol 182 (1) ◽  
pp. 29-37
Author(s):  
P.E. Schurr ◽  
H.T. Thompson ◽  
L.M. Henderson ◽  
C.A. Elvehjem
Keyword(s):  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Rat Organs

Proteolysis and formation of volatile compounds in cheese manufactured with a bacteriocin-producing adjunct culture

2001 ◽  
Vol 68 (1) ◽  
pp. 117-129 ◽  
Author(s):  
ABDELGHANI OUMER ◽  
PILAR GAYA ◽  
ESTRELLA FERNÁNDEZ-GARCÍA ◽  
RAÚL MARIACA ◽  
SONIA GARDE ◽  
...  
Keyword(s):  
Amino Acids ◽  
Enterococcus Faecalis ◽  
Free Amino Acids ◽  
Free Amino ◽  
Leuconostoc Mesenteroides ◽  
Aminopeptidase Activity ◽  
Hydrophobic Peptides ◽  
Bacteriocin Producer ◽  
Total Free Amino Acids ◽  
Adjunct Culture

Hispánico cheese, a semi-hard Spanish variety, was manufactured from a mixture of pasteurized cows' and ewes' milks (4[ratio ]1) using a commercial mesophilic LD-type starter comprising Lactococcus lactis subsp. cremoris, Lc. lactis subsp. lactis, Lc. lactis subsp. lactis var diacetylactis and Leuconostoc mesenteroides subsp. cremoris. Varying amounts (0–1·0 g/kg) of an Enterococcus faecalis INIA 4 culture in milk were added as a bacteriocin-producing adjunct. Differences in pH between cheeses manufactured with and without the bacteriocin producer did not exceed 0·11 pH units. Starter lactococci lost viability more rapidly in cheeses made with the bacteriocin producer, which reached counts of up to 6×107 cfu/g during ripening. Aminopeptidase activity in 1-d-old cheese made from milk inoculated with 1·0 g bacteriocin-producing culture/kg was twice that in control cheese. Degrees of overall proteolysis and levels of total free amino acids in 45-d-old cheese made with 1·0 g bacteriocin-producing culture/kg were 1·80-fold and 2·17-fold those in control cheese of the same age. Inoculating milk with 1·0 g/kg bacteriocin-producing culture reduced the level of hydrophobic peptides in the resultant cheese, increased the concentrations of 3-methyl-1-butanal, diacetyl and acetoin, and resulted in the highest scores for flavour quality and flavour intensity throughout ripening.

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