A high performance gel filtration chromatography method for gamma-glutamyltransferase fraction analysis.
The clinical relevance of serum gamma-glutamyltransferase (GGT) activity, in areas other than hepatic function, has recently been increased by several epidemiological associations. Still, GGT remains a nonspecific test because of the influence of various pathophysiological factors. We devised a procedure based on gel filtration chromatography, followed by postcolumn injection of fluorescent GGT substrate (gamma-glutamyl-7-amido-4-methylcoumarin), permitting the quantification of GGT fractions in serum or plasma. Plasma GGT molecular weight distribution was analyzed in healthy volunteers (20 males; mean+/-SD age 38+/-10 years; 20 females; age 44+/-13; total GGT 21+/-11 for males vs 13+/-7 for females; P<0.01). The method is highly sensitive (determination limit: 0.5 U GGT/L), with a linear dynamic range between 0.5 and 150 U/L for each fraction. Four GGT fractions of different molecular weight were detected in all subjects of both genders: b-GGT, m-GGT, s-GGT (likely lipoprotein-bound, molecular masses >2000, 940, and 140kDa, respectively), and a free fraction (f-GGT, 70kDa). f-GGT and s-GGT were the main fractions in subjects with lower and higher total GGT activity, respectively. Higher total GGT activity in males is related mainly to f-GGT (P<0.01). GGT fraction analysis may increase the sensitivity and specificity of the GGT activity test.
Franzini
Maria
M
Scuola Superiore S. Anna, Pisa, Italy.
Bramanti
Emilia
E
Ottaviano
Virginia
V
Ghiri
Emiliano
E
Scatena
Fabrizio
F
Barsacchi
Renata
R
Pompella
Alfonso
A
Donato
Luigi
L
Emdin
Michele
M
Paolicchi
Aldo
A
D000328:Adult; D002850:Chromatography, Gel / Q000379:methods*; D003374:Coumarins / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012737:Sex Factors; D005723:gamma-Glutamyltransferase / Q000097:blood* / Q000302:isolation & purification
D003374:Coumarins; C527911:gamma-glutamyl-7-amido-methylcoumarin; D005723:gamma-Glutamyltransferase