ABSTRACT
Vitamins ar e essentia l i n mammal ia n physiolog y becaus e thei r coenzym e
forms ar e prostheti c group s o r cofactor s i n man y enzym e reaction s o r becaus e
they ca n perfor m certai n specialized function s i n th e h u m a n organism . Vi tami n
A an d its role in the visua l process i s an example. Th e biology o f vitamins m ay b e
examined fro m th e nutritiona l o r biochemica l point s o f view . T h e forme r i s
concerned wi t h m i n i m u m dail y requirements , dietar y sources , bioavailability ,
and deficienc y syndromes . Th e biochemis t look s fo r structures , functiona l
groups, conversio n t o coenzymes , mechanism s o f action , mode o f transport , an d
storage. Bot h aspects wi l l b e addresse d i n this chapter , thoug h th e emphasi s wi l l
be o n th e biochemica l propertie s o f vitamins .
