TY - JOUR
T1 - Protein precipitation assay for quantitation of tannins
T2 - Determination of protein in tannin-protein complex
AU - Makkar, Harinder Paul S.
AU - Dawra, Rajinder K.
AU - Singh, Bhupinder
PY - 1987/11/1
Y1 - 1987/11/1
N2 - A protein precipitation method for the determination of tannins has been developed. The protein in the tannin-protein complexes was measured using the ninhydrin assay of amino acids released by alkaline hydrolysis of the complex. Standard protein and the complex were hydrolyzed with 13.5 n NaOH at 120°C for 20 min and the amino acids released were measured with ninhydrin. Tannins did not interfere in the determination of protein by ninhydrin assay. The bovine serum albumin (BSA) precipitated (y;mg) increased linearly with increase in tannic acid (x) from 0.2 to 0.9 mg (y = 2.598x - 0.258). The protein precipitation capacities (mg BSA precipitated/g dry wt) measured by the method for young and mature leaves of oaks were Quercus incana (young, 42.21; mature, 79.51), Q. ilex (young, 1.86; mature, 1.86), and Q. semecarpifolia (young, 733.54; mature, 304.32). The method can provide valuable information on the mechanisms of protein-tannin interactions and nutritional and physiological significances of tannins.
AB - A protein precipitation method for the determination of tannins has been developed. The protein in the tannin-protein complexes was measured using the ninhydrin assay of amino acids released by alkaline hydrolysis of the complex. Standard protein and the complex were hydrolyzed with 13.5 n NaOH at 120°C for 20 min and the amino acids released were measured with ninhydrin. Tannins did not interfere in the determination of protein by ninhydrin assay. The bovine serum albumin (BSA) precipitated (y;mg) increased linearly with increase in tannic acid (x) from 0.2 to 0.9 mg (y = 2.598x - 0.258). The protein precipitation capacities (mg BSA precipitated/g dry wt) measured by the method for young and mature leaves of oaks were Quercus incana (young, 42.21; mature, 79.51), Q. ilex (young, 1.86; mature, 1.86), and Q. semecarpifolia (young, 733.54; mature, 304.32). The method can provide valuable information on the mechanisms of protein-tannin interactions and nutritional and physiological significances of tannins.
KW - ninhydrin
KW - protein-tannin complex
KW - tannin determination
UR - http://www.scopus.com/inward/record.url?scp=0023441294&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023441294&partnerID=8YFLogxK
U2 - 10.1016/0003-2697(87)90596-3
DO - 10.1016/0003-2697(87)90596-3
M3 - Article
C2 - 3434784
AN - SCOPUS:0023441294
SN - 0003-2697
VL - 166
SP - 435
EP - 439
JO - Analytical Biochemistry
JF - Analytical Biochemistry
IS - 2
ER -