Chapter 16 

 THIAMINE 



Page 



I. Nomenclature 404 



II. Chemistry 404 



A. Isolation 404 



B. Chemical and Physical Properties 406 



C. Constitution 406 



D. Synthesis 406 



E. Specificity 408 



III. Industrial Preparation 409 



A. From Natural Sources 409 



1. Low Concentrates from Rice Bran or Polishings 409 



2. Low Concentrates from Yeast 410 



3. High Concentrates from Rice Germs 410 



4. Isolation of Crystalline Thiamine from Natural Sources .... 410 



B. Biosynthesis of Thiamine in Yeast 411 



C. Synthesis 411 



D. Patent Situation 424 



E. Commercial Forms and Purity 425 



F. Production and Prices 425 



IV. Biochemical Systems 426 



A. Enz}-mes 426 



1. The Unitarian View 433 



2. Coupling of Pyruvic Acid Oxidation with Phosphorylation . . . 434 



3. Inhibitors and Activators 436 



B. Coenzymes 437 



1. Chemical Procedure 438 



2. Enzymic Synthesis 438 



V. Specificity of Action 442 



A. The Essential Metals 442 



li. Thiamine Pyrophosphate 442 



C. Substrate Specificity 443 



\T. liiogenesis 445 



VII. Estimation 448 



A. Physical 448 



B. Chemical 448 



C. Biological 450 



D. Fermentation 450 



E. Microbiological 451 



VIII. Standardization of Activity 453 



IX. Occurrence in Food 454 



k. Occurrence of Thiamine and Its Phosphate Compounds 454 



B. Occurrence of Natural Antithiamines and Thiaminases in Foods . . 458 



403 



