Phosphoserine mammalian

There are two prominent types of mammalian cAMP-dependent protein kinases.51 61 The catalytic subunit is identical for both the 41-kDa peptide as isolated from beef heart has 350 residues and an N terminus blocked by a myristoyl (tetradecanoyl) group.62 One phosphoserine and one phosphothreonine are also present.51 The 50-kDa regulatory subunits vary in size and may also be subject to additional regulation by phosphorylation.63 Three-dimensional structures are known for both the catalytic62 64 65 and the regulatory66 subunits. A cyclic GMP (cGMP)-activated protein... 

Protein phosphatases (PPs) are a class of mammalian regulatory enzymes that catalyze the dephosphorylation of phosphoserine and phosphothreonine residues in proteins. Specific processes known to be controlled by protein phosphatases include glycogen metabolism, muscle contraction, mitosis, and transduction of hormonal signals. In the last 15 years, it has become... 

The work of Hubscher (1962) and Borkenhagen, Kennedy and Fielding (1961) indicates that in mammalian tissues phosphatidyl serine (IX) is not formed by the transfer of (9-phosphoserine from CDP-serine to D-cx,j8-diglyceride by a reaction analogous to those already described for the formation of lecithin and phosphatidyl ethanolamine (Reactions 12 and 19). Apparently free serine and not 0-phosphoserine is the immediate precursor of phosphatidyl serine. Serine displaces ethanolamine from phosphatidyl ethanolamine in an enzymic reaction activated by Ca and not requiring ATP ... 

APases are widely distributed in prokaryotes as well as in eukaryotes (1) . All purified enzymes are dimeric Zn(lI)-metalloenzymes with an active-site Ser which forms a covalent phosphoserine intermediate during catalysis (2). The molecular sizes range from 80 to 220 kDa per dimer, and mammalian enzymes are generally... 

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