Biochemical characterization of the minor immunophilins.
OBJECTIVE
We present biochemical characterization of the previously described 14 kDa, 37 kDa, and 52 kDa immunophilins and a newly identified 5-8 kDa immunophilin.


METHODS
Proteins were tested for the following enzymatic activities-rotamase, G3PDH, protein kinase C, cAMP dependent protein kinase-and for the ability to inhibit calcineurin phosphatase when complexed with tacrolimus (FK506).


RESULTS
The 5-8 kDa protein, like the other minor immunophilins, lacks rotamase activity. Since the 37 kDa possesses G3PDH activity, the 5-8 kDa protein, 14 kDa protein, and 52 kDa protein were all tested and found to lack G3PDH activity. Additional work shows that none of the minor immunophilins possess protein kinase C or cyclic AMP-dependent protein kinase activity and that the 37 kDa and 5-8 kDa and probably the 52 kDa proteins are capable of inhibiting calcineurin phosphatase when bound to tacrolimus.
Davis
D L
DL
Department of Laboratory Medicine, Children's National Medical Center, Washington, DC 20010, USA.
Murthy
J N
JN
Soldin
S J
SJ
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D006801:Humans; D020104:Immunophilins / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D007527:Isoenzymes / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D019169:Jurkat Cells; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010748:Phosphopeptides / Q000737:chemistry / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors; D011493:Protein Kinase C / Q000378:metabolism; D016559:Tacrolimus / Q000494:pharmacology; D022021:Tacrolimus Binding Proteins; D013950:Thymus Gland / Q000201:enzymology
D007527:Isoenzymes; D010748:Phosphopeptides; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; C120817:calcineurin phosphatase; D010744:Phosphoric Monoester Hydrolases; D022021:Tacrolimus Binding Proteins; D020104:Immunophilins; D016559:Tacrolimus