CHARACTERIZATION OF PHOSPHATE-TRANSPORT IN STREPTOMYCES GRANATICOLOR

Transport of inorganic phosphate in Streptomyces granaticolor was char acterized in two growth stages; kinetic parameters were determined and two transport systems were found in both stages, with the following v alues: K-T1 = 0.06 mM, J(lim1) = 0.95 nmol min(-1) (mg DS)(-1), and K- T2 = 1.80 mM, J(lim2) = 25 nmol min(-1) (mg DS)(-1). Both systems requ ire metabolic energy and substrates, such as sugars or polyols; when a lanine was used or the energy source was omitted, the kinetic paramete rs changed in both systems. Both systems were inhibited by the ionopho re CCCP with identical K-i. KCN, an inhibitor of terminal cytochrome o xidase, inhibited the uptake of phosphate only partially, the uptake w as inhibited completely when also the inhibitor of the alternative oxi dative pathway (salicylhydroxamic acid) was added. Antimycin A inhibit ed the uptake completely. Arsenate inhibited competitively.