INTERACTION OF HUMAN PLACENTAL RIBONUCLEASE WITH PLACENTAL RIBONUCLEASE INHIBITOR

被引:81
作者
SHAPIRO, R [1 ]
VALLEE, BL [1 ]
机构
[1] HARVARD UNIV,SCH MED,CTR BIOCHEM & BIOPHYS SCI & MED,SEELEY G MUDD BLDG,ROOM 106,BOSTON,MA 02115
关键词
D O I
10.1021/bi00222a030
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The interactions of human placental ribonuclease inhibitor (PRI) with bovine pancreatic ribonuclease (RNase) A and human angiogenin, a plasma protein that induces blood vessel formation, have been characterized in detail in earlier studies. However, studies on the interaction of PRI with the RNase(s) indigenous to placenta have not been performed previously, nor have any placental RNases been identified. In the present work, the major human placental RNase (PR) was purified to homogeneity by a five-step procedure and was obtained in a yield of 110-mu-g/kg of tissue. The placental content of angiogenin was also examined and was found to be at least 10-fold lower than that of PR. On the basis of its amino acid composition, amino-terminal sequence, and catalytic properties, PR appears to be identical with an RNase previously isolated from eosinophils (eosinophil-derived neurotoxin), liver, and urine. The apparent second-order rate constant of association for the PR-PRI complex, measured by examining the competition between PR and angiogenin for PRI, is 1.9 X 10(8) M-1 s-1. The rate constant for dissociation of the complex, determined by HPLC measurement of the rate of release of PR from its complex with PRI in the presence of a scavenger for free PRI, is 1.8 X 10(-7) s-1. Thus the K(i) value for the PR-PRI complex is 9 X 10(-16) M, similar to that obtained with angiogenin, and 40-fold lower than that measured with RNase A. Complex formation causes a small red shift in the protein fluorescence emission spectrum, with no significant change in overall intensity. The fluorescence quantum yield of PR and the Stern-Volmer constant for fluorescence quenching by acrylamide are both high, possibly due to the presence of an unusual posttranslationally modified tryptophan residue at position 7 in the primary sequence.
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页码:2246 / 2255
页数:10
相关论文
共 71 条
[1]  
BARKER RL, 1989, J IMMUNOL, V143, P952
[2]   MAGNETIC CIRCULAR-DICHROISM STUDIES .23. MAGNETIC CIRCULAR-DICHROISM SPECTRA OF INDOLE ALKALOIDS [J].
BARTH, G ;
BUNNENBERG, E ;
DJERASSI, C ;
LINDER, RE .
HELVETICA CHIMICA ACTA, 1972, 55 (06) :2168-+
[3]   ULTRAVIOLET ABSORPTION SPECTRA OF PROTEINS AND AMINO ACIDS [J].
BEAVEN, GH ;
HOLIDAY, ER .
ADVANCES IN PROTEIN CHEMISTRY, 1952, 7 :319-386
[4]   TIME-RESOLVED FLUORESCENCE OF PROTEINS [J].
BEECHEM, JM ;
BRAND, L .
ANNUAL REVIEW OF BIOCHEMISTRY, 1985, 54 :43-71
[5]   AMINO-ACID SEQUENCE OF THE NONSECRETORY RIBONUCLEASE OF HUMAN-URINE [J].
BEINTEMA, JJ ;
HOFSTEENGE, J ;
IWAMA, M ;
MORITA, T ;
OHGI, K ;
IRIE, M ;
SUGIYAMA, RH ;
SCHIEVEN, GL ;
DEKKER, CA ;
GLITZ, DG .
BIOCHEMISTRY, 1988, 27 (12) :4530-4538
[6]   MOLECULAR EVOLUTION OF THE RIBONUCLEASE SUPERFAMILY [J].
BEINTEMA, JJ ;
SCHULLER, C ;
IRIE, M ;
CARSANA, A .
PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY, 1988, 51 (03) :165-192
[7]   THE AMINO-ACID-SEQUENCE OF HUMAN PANCREATIC RIBONUCLEASE [J].
BEINTEMA, JJ ;
WIETZES, P ;
WEICKMANN, JL ;
GLITZ, DG .
ANALYTICAL BIOCHEMISTRY, 1984, 136 (01) :48-64
[8]  
BEINTEMA JJ, 1987, LIFE CHEM REPORTS, V4, P333
[9]  
BLACKBURN P, 1977, J BIOL CHEM, V252, P5904
[10]  
Blackburn P, 1982, ENZYMES, VXV, P317