[Quaternary structure of a cytoplasmic protein with ribonuclease activity from wheate seedling leaves. Kinetic manifestation of its "native", dissociated and reassociated forms]. / Chetvertichnaia struktura tsitoplazmaticheskogo belka s ribonukleaznoi aktivnost'iu iz list'ev prorostkov pshenitsy. Kineticheskie proiavleniia ego "nativnoi" dissotsiirovannoi reassotsiirovannoi form.

Previous data on oligomeric nature and values of molecular masses of "native" and dissociated forms of cytoplasmic protein with ribonulcease activity from wheat seedling leaves (Bezenchukskaya 98) are confirmed by means of polyacrylamide gel disc electrophoresis. Possible relation of the "native" enzyme form with 3':5'-cAMP is demonstrated by paper chromatography and the enzyme reassociation by the nucleotide. Study of kinetic manifestation of "native", dissociated and reassociated enzyme forms has revealed that the enzyme in the "normal" state has probably at least two active sites, "negative" homotropic cooperative interaction being establish-d between them at the definite degree of substrate saturation. The cooperativity disappears under dissociation, and it is discovered again under reassociation.