(BQ) Part 2 book "Handbook of vitamins" has contents: Vitamin B6, biotin, folic acid, vitamin B12, choline, vitamin - Dependent modifications of chromatin - Epigenetic events and genomic stability, dietary reference intakes for vitamins. | This Page Intentionally Left Blank 10 Vitamin B 6 JAMES E. LEKLEM Oregon State University, Corvallis, Oregon I. INTRODUCTION AND HISTORY Vitamin B 6 is unique among the water-soluble vitamins with respect to the numerous functions it serves and its metabolism and chemistry. Within the past few years the attention this vitamin has received has increased dramatically (1–8). Lay publications (9) attest to the interest in vitamin B 6. This chapter will provide an overview of vitamin B 6 as it relates to human nutrition. Both qualitative and quantitative information will be provided in an attempt to indicate the importance of this vitamin within the context of health and disease in humans. As a nutritionist, my perspective no doubt is biased by these nutritional elements of this vitamin. The exhaustive literature on the intriguing chemistry of the vitamin will not be dealt with in any detail, except as related to the function of vitamin B 6 as a coenzyme. To the extent that literature is available, reference will be made to research in humans, with animal or other experimental work included as necessary. As we leave the twentieth century behind, there may be a tendency to lose the sense of excitement of discovery that Gyorgy and colleagues experienced when they began to unravel the mystery of vitamin B complex. Some of the major highlights of the early years of vitamin B 6 research are presented in Table 1. Paul Gyorgy was first to use the term vitamin B 6 (10). The term was used to distinguish this factor from other hypothetical growth factors B 3 , B 4 , B 5 (and Y). Some 4 years later (1938), in what is a fine example of cooperation and friendship, Gyorgy (11) and Lepkovsky (12) reported the isolation of pure crystalline vitamin B 6 . Three other groups also reported the isolation of vitamin B 6 that same year (13–15). Shortly after this, Harris and Folkers (16) as well as Kuhn et al. (17) determined that vitamin B 6 was a pyridine derivative and structurally .
