Class of enzymes
Thiamine
Thiaminase is an enzyme that metabolizes or breaks down thiamine into pyrimidine and thiazole. It is an antinutrient when consumed.
The old name was "aneurinase".[ 1]
There are two types with different Enzyme Commission numbers :[ 2]
Thiamine pyridinylase, Thiaminase I (EC 2.5.1.2 , InterPro : IPR030901 )
pyridine + thiamine <=> 5-(2-hydroxyethyl)-4-methylthiazole + heteropyrithiamine[ 3]
Secreted by Paenibacillus thiaminolyticus ,[ 4] an anaerobic organism that occurs in the human small intestine
Aminopyrimidine aminohydrolase, Thinaminase II (EC 3.5.99.2 , InterPro : IPR027574 , IPR004305 )
4-amino-5-aminomethyl-2-methylpyrimidine + H2 O <=> 4-amino-5-hydroxymethyl-2-methylpyrimidine + NH2 + [ 5]
H2 O + thiamine <=> 4-amino-5-hydroxymethyl-2-methylpyrimidine + 5-(2-hydroxyethyl)-4-methylthiazole + H+ [ 5]
Produced by a wide range of plants and bacteria. In these organisms, it is mainly responsible for salvage of thiamine pyrimidine from degradation products, rather than the breakdown of thiamine.[ 5] In bacteria, it stays inside their cells.[ 6]