Affiliation:
1. Genetics Institute, Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32610-3610
Abstract
ABSTRACT
Cinnamic acids (i.e., ferulic and caffeic acids) that are esterified to the vegetable cell walls should be enzymatically released to be absorbed in a mammal's intestines. A low dosage of ferulic acid in rodent diets stimulates insulin production and alleviates symptoms caused by diabetes (M. Sri Balasubashini, R. Rukkumani, and V. P. Menon, Acta Diabetol. 40:118-122, 2003). Several lactic acid bacteria are able to display ferulic acid esterase (FAE) activity, suggesting that their probiotic activity could be, in part, mediated by the slow release of ferulic acid. In the present work, we describe the isolation of one strain identified as being
Lactobacillus johnsonii
that displayed strong FAE activity in stool samples from diabetes-resistant biobreeding rats. These animals are genetically susceptible to becoming diabetic but do not develop the disease. By using genomic analysis coupled to protein purification and catalytic screening, we were able to purify two proteins with FAE activity. The enzymes displayed 42% sequence identity and a broad range of substrate preferences. High affinities and catalytic efficiencies toward aromatic compounds such as ethyl ferulate (
K
m
= 20 to 60 μM) and chlorogenic acid (
K
m
= 10 to 50 μM) were observed. The strain isolated herein as well as the enzymes studied could be potentially useful for the formulation of probiotics to ameliorate diabetes symptoms.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
114 articles.
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