当前位置： SCI文献检索 > MOLECULAR AND CELLULAR BIOCHEMISTRY期刊下所有文献 > Depressed sliding velocity of isolated cardiac myosin from cardiomyopathic hamsters: evidence for an alteration in mechanical interaction of actomyosin.

Depressed sliding velocity of isolated cardiac myosin from cardiomyopathic hamsters: evidence for an alteration in mechanical interaction of actomyosin.

Abstract：

:We measured the relative sliding velocity of cardiomyopathic hamster cardiac myosin on actin cables by using an in vitro motility assay system. We also investigated the relationship between the velocity and both myosin isozyme content and ATPase activity. Cardiac myosin was obtained from cardiomyopathic hamsters (BIO 14.6; B) aged 3, 6, 9, and 18 months and age-matched controls (F1B; F). Long well-organized actin cables of an alga, Nitellopsis, were used for the motility assay. Small latex beads (2 microns in diameter) were coated with purified cardiac myosin. When myosin-coated beads were introduced into an algal cell in the presence of Mg-ATP, myosin interacted with actin and dragged the beads. Active movement of the beads along the actin cables was observed under a photomicroscope and the velocity was measured. The velocity was significantly lower in B than in F for each age group (0.47 vs. 0.71 microns/s at the age of 3 months, p < 0.05; 0.44 vs. 0.88 microns/s at 6 months, p < 0.01; 0.44 vs. 0.67 microns/s at 9 months, p < 0.01; 0.35 vs. 0.52 microns/s at 18 months, p < 0.05). Both Ca(2+)-activated ATPase activity and the percentage of alpha-myosin heavy chain were also lower in B than in F for each age group. When examined for individual specimens, there was a positive correlation between the velocity and both myosin Ca(2+)-activated ATPase activity (r = 0.84) and percentage of alpha-myosin heavy chain (r = 0.83). These data points of both control and cardiomyopathic hamsters were distributed near the regression line obtained from control and thyroxine-treated rabbits reported previously. The present results indicate that the difference in mechanical properties between control and cardiomyopathic cardiac myosin is attributed to isozyme redistribution and not to a qualitative change in each myosin molecule.

journal_name

Mol Cell Biochem

journal_title

Molecular and cellular biochemistry

authors

Yamashita H,Sugiura S,Sata M,Serizawa T,Iizuka M,Shimmen T,Momomura S

doi

10.1007/BF00926857

subject

Has Abstract

pub_date

1993-02-17 00:00:00

pages

79-88

issue

1-2

eissn

0300-8177

issn

1573-4919

journal_volume

119

pub_type

杂志文章

在线工具

Depressed sliding velocity of isolated cardiac myosin from cardiomyopathic hamsters: evidence for an alteration in mechanical interaction of actomyosin.