Biomedical subjects

N F Krauzova

Publications and source records attributed to N F Krauzova.

3 recordsLinked to original sources

PubMed1986

[Nature of the changes in the activity of water-soluble enzymes in exposure of muscles to harmful agents. IV. The study of hexokinase extractability from intact and altered muscles].

A possibility of hexokinase binding with actomyosin in skeletal muscles of Rana temporaria L., and the effect of thermal alteration (15 min at 36, 37, 38, 40 and 42 degrees C) on the binding were studied. Solutions of KCl (0.075 M and 0.15 M) extract more hexokinase from intact and altered muscles than does an non-electrolyte medium. Hexokinase freely dissolved in hyaloplasm is extracted in non-electrolyte medium. Hexokinase bound with structural components of the muscle cell is extracted upon the increase in ionic force of the extractant. The solubilizing effect of electrolytes on hexokinase is higher in alterated muscles than in the intact muscles indicating the increase in hexokinase binding under thermal alteration. Actomysin isolated from muscles reveals hexokinase activity. In reprecipitated actomyosin, the larger part of its hexokinase remains in actomyosin gel, the level of hexokinase activity not depending on the number of reprecipitation procedures or on the volume of washing solution. Hexokinase in actomyosin gel is less stable to the thermal action than in water supernatant of muscle extract. This may be due to the increase in hexokinase binding with actomiosin whose sorption activity increases under the thermal denaturation.

Actomyosin↗

PubMed1984

[Changes in hexokinase activity during muscle alteration].

Changes in extractability and activity of hexokinase (HK) were studied under the action of heating and of urea on skeletal muscles of Rana temporaria L., and besides the stability of this enzyme in muscle extract to those agents in vitro was examined. Under a 15 minutes heating of muscle, a decrease in extractability (the activity calculated for 1 g of tissue) and activity (the activity calculated for 1 mg of protein) of hexokinase is first revealed at 37 degrees C. Then the enzyme extractability decreases gradually in accordance to the decrease in extractability of the total water-soluble protein; the level of hexokinase activity attained at 37 degrees does not change up to 40 degrees. At 42 degrees the activity of the enzyme is completely inhibited. Under the heating of the muscle extract, the decrease of enzyme activity takes place at 36 degrees, the level achieved being stable up to 42 degrees C. Under the action of urea on the muscle at the reversible phase of alteration (1 M urea from 5 minutes to 2 hours at room temperature, 1 M urea for 9 hours at + 4 degrees C), hexokinase activity increases, calculated for 1 g of tissue and for 1 mg of protein. Under the irreversible disappearance of muscle excitability (1 M urea during 9 hours, 2 M urea during 2 hours at room temperature) no hexokinase activity was revealed. The activation of the enzyme is discussed in connection with the data on the increase of ATP content in muscle under the urea alteration. The treatment of the enzyme in muscle extract with 1 M urea decreases its activity in 30 minutes down to 67%; the level achieved does not change during 20 hours.

Aerobiosis↗

PubMed1983

[Nature of the changes in water-soluble enzyme activity in the exposure of muscles to harmful agents. III. A study of creatine kinase extractability from intact and altered muscles].

Binding of creatine kinase (CrK) in intact and thermally altered (15 minutes at 37 and 38 degrees C) skeletal muscles of frogs (Rana temporaria L.) was studied according to CrK extractability from muscles. The CrK activity in actomyosin isolated from muscles and its changes in thermally altered actomyosin were detected. Solutions of KCl (0.075, 0.15, 0.3 and 0.6 M) and of NaF (0.15 M) extract additional amounts of CrK from intact and altered muscles. Inhibiting effects of KCl, NaF and K2HPO4 on CrK in muscle extract were found. The latter exerts the most pronounced inhibiting effect, which prevents it from being used for CrK extraction purposes. Among the structural components of muscle that bind CrK actomyosin was detected. The actomyosin isolated from muscles revealed CrK activity. CrK in actomyosin gel is much more stable to thermal effect than that in a water extract of muscle. Such a thermostabity of CrK within the system of the whole muscle cell may apparently result from its being bound to actomyosin.

Actomyosin↗