formation on surface was calculated utilizing the absorption coefficient/scattering coefficient (K/S) ratios and formulas according to AMSA , and the MRA was estimated using the following equation:
Briefly, 20 ul of serum sample (or standard, 6-hydroxy-2,5,7,8- tetramethylchroman-2-carboxylic acid) was incubated with 1 ml of chromogen (consisting of metmyoglobin
and ABTS(r)) at 37degC in a cuvette in temperature-controlled spectrophotometer.
TAC measurement was based on the ability of antioxidants in the plasma to inhibit the oxidation of ABTS[R] (2,2'-Azino-di- to [ABTS[R].sup.-+] by metmyoglobin
 stated that the evolution of metmyoglobin
, oxymioglobin and myoglobin in beef samples, despite the stressing conditions due to the fighting and to the high pH values, was similar to the values observed in animals slaughtered under usual conditions at the slaughter house.
This assay relies on the ability of antioxidants in the plasma to inhibit oxidation of 2,2' azino-bis-[3-ethylbenz-thiazoline-6-sulfonic acid] (ABTS) to [ABTS.sup.+] by metmyoglobin
. The amount of ABTS+ produced was monitored by reading the absorbance at 600 nm.
The assay relies on the ability of antioxidants to inhibit the oxidation of ABTS' (2, 2'-Azino di-[3-ethylbenzthiazoline sulphonate] to ABTS" by metmyoglobin
. The amount of ABTS" produced was monitored by reading the absorbance at 750 nm or 405 nm.
[8.] Bekhit AED, Geesink GH, Llian MN, Morton JD and R Bickerstaffe The effects of natural antioxidants on oxidative processes and metmyoglobin
reducing activity in beef patties.
2,2'-Azino-di 3-ethybenzthiazoline sulphonate) (ABTS) was incubated with a peroxidase (metmyoglobin
) and [H.sub.2][O.sub.2] to produce the radical cation ABTS.
The methemyoglobin (metHb) and metmyoglobin
(metMb) thus generated, as well as their derivatives are capable to produce more ROS, besides lipid peroxidation, with formation of hydroperoxides (59,62).
The peak corresponding to metmyoglobin
reduction appears at around -0.25 V in the Nafion and sol-gel matrices.
The TEAC assay, commercialized by Randox Laboratories Ltd., is based on the suppression of the absorbance of radical cations of 2,2'-azinobis(3-ethylbenzothiazoline 6-sulfonate) (ABTS) by antioxidants in the test sample when ABTS incubates with a peroxidase (metmyoglobin
) and [H.sub.2][O.sub.2] (1).
Even protein structures such as the 1261 atom metmyoglobin
have been refined from high-resolution synchrotron x-ray powder data .