pH-induced transition and Zn2+-binding properties of bovine prolactin.
A pH-induced conformational transition was found in bovine prolactin within the physiologically significant pH region from 6.5 to 8.5. The thermal stability of prolactin at pH 6.5 is essentially higher than at pH 8.5. Bovine prolactin binds zinc ions with an apparent association constant of 2 x 10(5) M(-1) at pH 6.5 and 1 x 10(4) M(-1) at pH 8.5. The pH dependence of both thermal stability and zinc binding surrounding the pKa of histidine suggests that these residues plays a key role in the structural integrity of bovine prolactin.
Permyakov
E A
EA
Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow region, Russian Federation.
Veprintsev
D B
DB
Deikus
G Y
GY
Permyakov
S E
SE
Kalinichenko
L P
LP
Grishchenko
V M
VM
Brooks
C L
CL
D000818:Animals; D002417:Cattle; D006639:Histidine / Q000737:chemistry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D011388:Prolactin / Q000737:chemistry*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D015032:Zinc / Q000737:chemistry*
D006639:Histidine; D011388:Prolactin; D015032:Zinc