Chikataro Kawasaki

MODIFIED THIAMINE COMPOUNDS.

Publisher Summary This chapter describes modified thiamine compounds. There has been a great increase in Japan in the sale of vitamin preparations containing thiamine, and also in the enrichment of staple foods, candies, and other food items with thiamine. This increase has encouraged the search for derivatives of thiamine that are odorless and more stable than its chloride-hydrochloride form. It has stimulated the successful development of modified thiamine compounds both for therapeutic and enrichment purposes. Modified thiamine compounds can be classified into two types: masked compounds which still retain thiamine activity in animals, and permanently altered compounds, which have no thiamine activity even though they are chemically convertible to thiamine to a greater or lesser extent. The masked thiamine compounds are interesting examples of successful changes of the thiamine molecule, and they may be superior to thiamine both in physical and in biochemical properties. Other vitamins than thiamine do not usually form this type of modified compound, these thiamine-active modified compounds may be divided into the disulfide and the S-acyl thiamine types.

[Studies on the mechanism of biosynthesis and accumulation of dipicolinic acid in spore-forming bacteria. I. Physical and chemical properties of an active fraction catalyzing synthesis of dipicolinic acid from the diketopimelate-NH3 complex].

An active fraction catalyzing synthesis of dipicolinic acid from the diketopimelate-NH3 complex was extracted from sporangium. Some physical and chemical properties of the fraction were investigated. The activity of this fraction was stable to heat treatment at 100°C for 2 hours and also to the proteinase digestion. The active fraction was dialysable against the cellophane and collodion membrane. When the effects of various reducing agents on the activity of the fraction were compared, it was found that the addition of β-mercaptoethanol to the reaction system showed a significant increase of dipicolinic acid formation. PCMB and monoiodeacetate partially inhibited the reaction. KCN completely inactivated the fraction. Neither acid hydrolysate nor ash of the fraction showed any activity.