The Biochemistry of Vitamin B12

entities, vitamin B12 and the intrinsic factor. Although these two entities are entirely different in chemical nctturc, they play a very significant j...
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BOOK REVIEWS The Biochemistry of Vitamin BI?. Biochemical Society of Ascorbic Acid,” b y hlapson, “The Role of Vitamin B1.!it1 Symposia KO. 13. -4 Symposium held a t The London the Metabolism of Microorganisms,” b y Ford and Hutner, School of Hygiene and Tropical Medicine on 19 February “The Chemotherapeutic Action of Vitamin Bls,” by Ungley, 1955. Organized and Edited b y R . T. ~VILLIAMS. Cain- and “ T h m i n Requirements of Human Beings,” by P c t t ; bridge University Press (American Branch), 32 E a s t 67th two articles dealing with other nutritional problems, “The Street, Xew York 22, S. Y. 1955. 123 pp. 16 X 25.5 Physiology and Biochemistry of the Essential F a t t y Acids, ” cm. Price, $3.75. by Deuel and Reiser, and “Parasitic Infections and NutriThis booklet contains seven chapters rvhich were organ- tion,” by Smith; and two articles concerned with tlie mechanism of hormonal action, “Hormones and Mitotic ized and edited b y R . T . m’illiams. T h e chapters correActivity,” by Bullough, and “Concerning Possible h1ecl:spond t o lectures which constituted a symposium on “The anisins of Hofmone Action,” by Hechter. I t is worthy o f Biochemistry of vitamin BI?” held in London on February note that the two chapters on vitamin B E , together with the 19, 1955. T h e introduction is by Sir ;\lexander Todd. Some of the chapters contain information t h a t was unpub- one in the previous volume, furnish a thorough account i d the chemistry, physiology and chemotherapeutics of this lished at t h e time of the Symposium, although each chapter anti-pernicious anemia factor, cyanocobalamin. is essentially a review of a given topic. I t is now well-established t h a t most vitamins act a i T h e subject is built around essentially tIro key cheinical coenzymes or co-factors in biocattilytic processes. On the entities, vitamin B12 and the intrinsic factor. Although other hand, little is knoirn about the inerlianism of 11ornion:il these two entities are entirely different in chemical nctturc, action. I t was therefore of special interest, particularly t i ) they play a very significant joint role in “the transfer of the reviewer, t o encounter the last two chapters in the one millionth gram of vitamin BI? the distance of a small present volume. Bullough, discussing the relationship o f fraction of a millimeter across the intestinal mucosa and iuto various hormones to mitosis, concluded that liortnone~ the bloodstream (Castle).” exercise their effects on epidermal mitosis through their T h e isolation and chemical studies of vitamin Biz were influence on the glucokinase system. I n this connection, the reviewed b y E. Lester Smith in a series of well organized sub-topics. T h e time limitation of the lecture necessitated author summarized data concerning the interaction betweel: insulin and pituitary growth hormone with respect t o mitotic a considerable abbreviation of the substantial amount of activity in mouse ear epidermis. From the observation literature material which falls under this heading. T h e discussion b y Dorothl- Hodgkin summarized the X-ray anal- that, whereas insulin stimulates the development of mitotic activity, growth hormone acts as a n inhibitor, questions ysis of vitamin B12, and the note added in proof contains a arise about either the biological nature of the growth h i r complete structural formulation. T h e subject of chemical inone or its function in connection with insulin. Thii and microbiological methods of nieasurement of vitamin Bi? furnishes just one example of the confusion which has ariscii and vitamin Bl?-like compounds was reviewed by Coates out of the terminology of the growth hormone, origitidl>and Ford. named on the basis of its most readily observable biological The still expanding group of new cobalt complexes which are related t o vitamin B12was recorded, classified and dis- effect. The last chapter, by 0. Hechter, is perhaps the most cussed in a n effective style by S. K. Kon. stimulating and thoughtful essay ever t o appear on tlic >ubThe two chapters on “The Function of Yitamin B12 in LIicroorganisms” by Lascelles and Cross, and “The Func- ject of the mechanisms of hormone action. The author points out t h a t despite the spectacular progress i i i Ino>t tion of Vitamin BI2 in Animal 3Ietabolism” by Arnstein, spheres of the research on hormones, there is as yet no r e d are veri- good and readable. understanding of the basic mechanisms of hormonal operatioil “The -1bsorption and Excretion of Vitamin BI? in M a n ” a t a cellular level. H e formulates two basic questions illwas surveyed b y Mollin and Baker. These studies in man volring the modes of hormone action, which have >-etto be were extended and facilitated by the availability of radioelucidated, “How can trace amounts of hormone produce priiactive vitamin R12. The early work mis done with vitamin BI?labeled with Co“. hIore recent studies were made with found biological effects in target cells without contributingxignificant amounts of either energy or matter t o the vitamin BE labeled with Cos6 (half-life i 2 d a j and “How can the specificity of hormone action be L (half-life 72 days). Samples of radioactive for?” After carefully reviewing the current concepts a!xut with high specific activities of 12 and 13.5 mc./nig. have been hormone action and discussing the available data on the made Irith Coj6 and C057 (Chapters I and IV). action of those three mammalian hormones, insulin, adrenLatner has reviewed the history, assay, purification and aline and ACTH, on which the present knowledge seem\ t!ic other related aspects of the intrinsic factor. I n summarizmost advanced, he concludes t h a t the hypothesis tllat ing the chemical nature of the intrinsic factor, Latner conemerges as possibly the most likely concept of hormune xction siders t h a t the mucoprotein nature is established. In reis one which in essence had suggested itself t o pioneer viewing the evidence on how the intrinsic factor is concerned pharmacologists man>->-earsago, namely, t h a t hornionci xct lvith the absorption of vitamin Bi?across the intestine, Latner concludes in favor of the ciincept of catalyzed absorption. bg regulating permeability relationships between cells and metabolites. However, he emphasizes the very relevant ~ Z E R C K & Co., I s c . point that, in view of the fact t h a t diverse types of clieinical RaHTYAY, S E T Y JERSEY KARLFOLKERSstructures can be subsumed under the present wrirkitig definition of hormone, perhaps it is not reasonable to exI)cet _____~_ t o uncover only one mode of action for all hormones. .41 : L I I ~ Vitamins a n d Hormones. Advances in Research and rate, as Hechter has very aptly said, “only xliei: thc ‘fine Applications. Trolume S I I I . Edited by ROBERT S. details’ of the cell niechanisn~supon which a hornione priHARRIS, Professor of Biochemistry of Xutrition, Massamarily acts have been dissected, will it be possible t o define chusetts Institute of Technology, Cambridge, Massa- hormone action in fundamental terms.” chusetts, G. F. MARRIAN, Professor of Medical Chemistry, I t is no small achievement on the part of the editors to University of Edinburgh, Edinburgh, Scotland, and have compiled a series t h a t covers so well the current tleKENNETH V. THIMANS, Professor of Plant Physiology, velopments in these two rapidly-advancing fields of vitamins Harvard University, Cambridge, Massachusetts. Acaand hormones. In addition, they have contributed somedemic Press, Inc., Publishers, 125 East 23rd Street, New thing more. I n recent years there have appeared inan?. York 10, S.Y . s i 382 pp, 16.5 X 23.5 cm. Price, series and review volumes recording the progress and listing 89.00. t h e new accomplishments in v;irious ficlds relatctl t o !>iochemistr>~-certninly no n i c ~ :goal in itself, iii view o f the Like its predecessors, this \-olume maintains the high standard of the series; it contains fivc articles on subjects rapid acceleration of iirogress t h a t Iias 1)ccn o1)scrvcti it1 b o many of tlicse fields-and yet it is not SI) often tilat a vtilulrle relating to vitamins: “The Role of t h e Vitamin in Antibody Production,” by ilxelrod and Pruzansky, “The Biosyuthcsii such as this unc appears, in which there is alsu a place for

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