Protein kinase activities in the parathyroid gland: proparathyroid hormone, parathyroid hormone and secretory protein-I as substrates for phosphorylation.
We have identified two protein kinase activities in homogenates of bovine parathyroid tissue following fractionation on DEAE columns. One of these is a protein kinase C based upon its requirement for calcium and phosphatidylserine and the other one is probably M kinase. The protein kinase C phosphorylated both proparathyroid hormone and parathyroid hormone but not secretory protein-I (SP-I). Neither N [1-34] or C [35-84] terminal hormonal fragments were phosphorylated, suggesting that the structure of the intact PTH molecule is required for recognition by the enzyme. A second kinase activity behaving like M kinase was also obtained. This activity, which was not separable from a cAMP dependent kinase, was maximal with only 50 mM MgCl2 as cofactor. SP-I was readily phosphorylated by this activity but parathyroid hormone was not.
Baty
L
L
Research Service, Veterans Administration Medical Center, Kansas City, MO 64128.
Rouse
J
J
Hamilton
J
J
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002417:Cattle; D053379:Chromogranin A; D002864:Chromogranins; D010280:Parathyroid Glands / Q000201:enzymology*; D010281:Parathyroid Hormone / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000032:analysis; D011494:Protein Kinases / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D053379:Chromogranin A; D002864:Chromogranins; D010281:Parathyroid Hormone; D011498:Protein Precursors; C003219:proparathormone; D011494:Protein Kinases; D011493:Protein Kinase C