Physarum polymalic acid hydrolase: Recombinant expression and enzyme activation.
As a platform for syntheses of nanoconjugates in antitumor drug delivery, polymalic acid together with its tailoring specific exohydrolase is purified from plasmodium cultures of the slime mold Physarum polycephalum, a member of the phylum myxomycota. Polymalic acid hydrolase is expressed in an inactive form that functions as a molecular adapter for polymalic acid trafficking within the plasmodium and is activated only during secretion. Activation follows specific protein tyrosine phosphorylation and dissociation from plasma membranes. Purified inactive Physarum polymalic acid hydrolase, recombinantly expressed in yeast Saccharomyces, is activated on a preparative basis by the addition of plasma membrane fragments from plasmodia of P. polycephalum. Activation of polymalic acid hydrolase and inhibition of polymalic acid synthesis by protein tyrosine phosphorylation are complementary events and could indicate a joint signal response to plasma membrane damage.
Biophysik und Physikalische Biochemie, Universitaet Regensburg, 93040 Regensburg, Germany.
Wolfgang
W
Mueller
Markus
M
Haindl
Eggehard
E
Holler
D000818:Animals; D003001:Cloning, Molecular; D004789:Enzyme Activation; D006867:Hydrolases / Q000302:isolation & purification / Q000502:physiology*; D008293:Malates / Q000378:metabolism*; D016839:Physarum polycephalum / Q000201:enzymology*; D011108:Polymers / Q000378:metabolism*; D015800:Protozoan Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000235:genetics
D008293:Malates; D011108:Polymers; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C121060:poly(malic acid); D006867:Hydrolases