A new enzymatic method for the determination of inulin.
A new enzymatic method for the determination of inulin in plasma and urine, using inulase (EC 3.2.1.7), fructokinase (EC 2.7.1.4), phosphoglucoisomerase (EC 5.3.1.9) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) is described. The assay is based on the hydrolysis of inulin or Inutest (INutest which is the injectable form of inulin), by inulase and the determination of fructose released. The assay was linear up to 2 g/L of Inutest. The within-batch and between batch coefficients of variation were 2.3% and 2.2%, respectively. Recovery of added Inutest from plasma and urine was 98-102%. There was no interference from glucose (27.7 mmol/L), fructose (1.7 mmol/L) or mannose (1.7 mmol/L). When inulin clearance (using this method) and thiosulphate clearance were compared in 37 patients the inulin clearance was 9.3 mL/min (12%) lower than the thiosulphate clearance. We conclude that this enzymatic method is a simple and specific method.
Sugita
O
O
Department of Laboratory Medicine, Niigata University School of Medicine, Japan.
Tomiyama
Y
Y
Matsuto
T
T
Okada
M
M
Gejyo
F
F
Arakawa
M
M
Takahashi
S
S
Watazu
Y
Y
Kaneda
N
N
D000873:Anthracenes / Q000378:metabolism; D005631:Fructokinases / Q000378:metabolism; D005632:Fructose / Q000032:analysis / Q000378:metabolism; D005919:Glomerular Filtration Rate; D005956:Glucose-6-Phosphate Isomerase / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006801:Humans; D007444:Inulin / Q000097:blood* / Q000652:urine*; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013379:Substrate Specificity; D013885:Thiosulfates / Q000032:analysis; D000095322:Anthrones
D000873:Anthracenes; D005631:Fructokinases; D005632:Fructose; D005956:Glucose-6-Phosphate Isomerase; D005954:Glucosephosphate Dehydrogenase; D006026:Glycoside Hydrolases; D007444:Inulin; D011933:Reagent Kits, Diagnostic; D013885:Thiosulfates; C046173:fructokinase; C023086:inulinase; C004522:anthrone; D000095322:Anthrones