Characterization of multiple molecular forms of Mg(2+)-dependent protein phosphatase from Saccharomyces cerevisiae.
Three molecular species of Mg(2+)-dependent protein phosphatase (MPPs-1, -2, and -3) were isolated by DEAE cellulose column chromatography and gel filtration from an extract of Saccharomyces cerevisiae. MPP-1 was further purified 150-fold by chromatography using thio-phosphorylated myosin light chain-agarose. MPPs-1, -2, and -3 were distinct from the major acid and alkaline phosphatases, and their activities were not affected by okadaic acid, microcystin-LR or Ca2+, and calmodulin, resembling the enzymatic properties of type 2C protein phosphatase of mammalian cells. The apparent molecular masses of MPPs-1, -2, and -3 on gel filtration were 53, 112, and 128 kDa, respectively. It was demonstrated that MPP-1 is a globular protein of 53-55 kDa and that MPPs-2 and -3 are oligomeric proteins that dissociate upon sucrose density gradient centrifugation, generating catalytic proteins of about 50 kDa. Since the substrate specificities of MPPs-1, -2, and -3 differed from each other both before and after sucrose density gradient centrifugation, it was suggested that the catalytic proteins of these three enzymes are distinct molecular species.
Murakami
T
T
Department of Biochemistry, Institute of Development, Aging and Cancer, Sendai.
Kobayashi
T
T
Terasawa
T
T
Ohnishi
M
M
Kato
S
S
Sasahara
Y
Y
Itoh
M
M
Nakano
T
T
Tamura
S
S
D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification*; D008387:Marine Toxins; D052998:Microcystins; D008970:Molecular Weight; D010456:Peptides, Cyclic / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000302:isolation & purification*; D010766:Phosphorylation; D000071636:Protein Phosphatase 2C; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013379:Substrate Specificity; D013439:Sulfhydryl Reagents
D007527:Isoenzymes; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D013439:Sulfhydryl Reagents; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C; C057862:cyanoginosin LR