title: Total myrosinase activity estimates in brassica vegetable produce.
abstract: Isothiocyanates, generated from the hydrolysis of glucosinolates in plants of the Brassicaceae family, promote health, including anticancer bioactivity. Hydrolysis requires the plant enzyme myrosinase, giving myrosinase a key role in health promotion by brassica vegetables. Myrosinase measurement typically involves isolating crude protein, potentially underestimating activity in whole foods. Myrosinase activity was estimated using unextracted fresh tissues of five broccoli and three kale cultivars, measuring the formation of allyl isothiocyanate (AITC) and/or glucose from exogenous sinigrin. A correlation between AITC and glucose formation was found, although activity was substantially lower measured as glucose release. Using exogenous sinigrin or endogenous glucoraphanin, concentrations of the hydrolysis products AITC and sulforaphane correlated (r = 0.859; p = 0.006), suggesting that broccoli shows no myrosinase selectivity among sinigrin and glucoraphanin. Measurement of AITC formation provides a novel, reliable estimation of myrosinase-dependent isothiocyanate formation suitable for use with whole vegetable food samples.
authors: Department of Food Science and Human Nutrition and ‡Department of Crop Sciences, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801-3838, United States.
authors: Edward B
authors: EB
authors: Dosz
authors: Kang-Mo
authors: KM
authors: Ku
authors: John A
authors: JA
authors: Juvik
authors: Elizabeth H
authors: EH
authors: Jeffery
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001937:Brassica / Q000201:enzymology*; D035264:Flowers / Q000201:enzymology*; D005628:Frozen Foods; D055951:Functional Food; D005947:Glucose / Q000032:analysis / Q000378:metabolism; D005961:Glucosinolates / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000378:metabolism*; D006868:Hydrolysis; D007087:Illinois; D017879:Isothiocyanates / Q000032:analysis / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D014674:Plant Proteins, Dietary / Q000737:chemistry / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology; D012995:Solubility; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D000975:Antioxidants; D005961:Glucosinolates; D017879:Isothiocyanates; D010940:Plant Proteins; D014674:Plant Proteins, Dietary; D006026:Glycoside Hydrolases; C022739:thioglucosidase; D005947:Glucose