STRUCTURE AND PROPERTIES OF HEMOCYANINS .6. ASSOCIATION-DISSOCIATION BEHAVIOR OF HELIX-POMATIA HEMOCYANIN

被引:66
作者
KONINGS, WN
SIEZEN, RJ
GRUBER, M
机构
[1] Biochemisch Laboratorium, The University, Groningen
关键词
D O I
10.1016/0005-2795(69)90098-1
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
1. 1. The association-dissociation behavior of α-hemocyanin of Helix pomatia was studied by ultracentrifugal analysis. 2. 2. Above pH 7 and below pH 5 whole molecules (102 S) dissociate into half (64 S) and tenth (20 S) molecules. At alkaline pH further dissociation is observed into twentieth (13 S) molecules (mol.wt. about 4.5 · 105), which are the smallest biologically active components that can be obtained. 3. 3. The dissociation is reversible in the pH range 4-11. Reassociation is induced by readjusting the pH to 5-7 or, at alkaline pH values, by the addition of bivalent cations. 4. 4. The pH-stability pattern and the near-independence of the degree of dissociation from the concentration indicate that dissociation is a co-operative process. 5. 5. The association-dissociation behavior does not obey the rules valid for a simple equilibrium; therefore a certain heterogeneity in the bonds between the structural units must exist. 6. 6. Whole molecules are dissociated into halves by hydrostatic pressure. This results in an elevated baseline between the two components in the Schlieren patterns. © 1969.
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页码:376 / &
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