Influences of pyridoxine derivatives on the biosynthesis and stability of pyridoxal phosphate enzymes.

Publisher Summary This chapter discusses the results obtained related to the involvement of pyridoxal phosphate and other pyridoxine derivatives on the biosynthesis and stability of pyridoxal phosphate-dependent enzymes. This survey of the available data has revealed that the regulation of the activities of pyridoxal phosphate enzymes even in so restricted a field as pyridoxal phosphate and other pyridoxine derivatives, is very complex. Remarkable differences have been observed, in responses to pyridoxine deficiency, depending on the enzyme under consideration. In general, the enzymes of the cell sap are far more sensitive to pyridoxine deprivation than the enzymes associated with the particulate fractions. The enzymes whose turnovers are high are more rapidly altered than the enzymes whose turnovers are low. This chapter reveals that pyridoxal phosphate and pyridoxine derivatives have interesting properties that afford some insight into the still rudimentary knowledge of the mechanism involved in the physiological biosynthesis and degradation of enzymes. Effects of pyridoxine deficiency are elaborated. Effects of pyridoxal phosphate and other pyridoxine derivatives on the stability of purified enzymes are also described.