Atkinson M M, Baker C J, Collmer A
University of Maryland, Department of Botany, College Park, Maryland.
Plant Physiol. 1986 Sep;82(1):142-6. doi: 10.1104/pp.82.1.142.
A purified pectate lyase isozyme derived from Erwinia chrysanthemi induced rapid net K(+) efflux and H(+) influx in suspension-cultured tobacco cells. Comparable fluxes of other ions (Na(+), Cl(-)) were not observed. The K(+) efflux/H(+) influx response began within 15 minutes after addition of enzyme to cell suspensions and continued for approximately 1 hour after which cells resumed the net H(+) efflux exhibited prior to enzyme treatment. The response was not prolonged by a second enzyme dose 1 hour after the first. The K(+)/H(+) response was characterized by saturation at low enzymic activity (2 x 10(-3) units per milliliter), and inhibition by the protonophore, carbonyl cyanide m-chlorophenylhydrazone, and was not associated with membrane leakiness caused by structural cell wall damage. The total K(+) loss and H(+) uptake induced by enzyme was one-fourth to one-third that induced by Pseudomonas syringae pv. pisi and did not reduce cell viability. These results indicate that pectate lyase induces a K(+) efflux/H(+) influx response in tobacco similar to but of shorter duration than that induced by P. syringae pv. pisi during the hypersensitive response. Pectate lyase or other cell wall degrading enzymes may therefore influence the induction of hypersensitivity.
一种从菊欧文氏菌中提取的纯化果胶酸裂解酶同工酶，能在悬浮培养的烟草细胞中诱导快速的净钾离子外流和氢离子内流。未观察到其他离子（钠离子、氯离子）有类似的通量变化。钾离子外流/氢离子内流反应在向细胞悬液中添加酶后的15分钟内开始，并持续约1小时，之后细胞恢复到酶处理前呈现的净氢离子外流状态。在第一次添加酶1小时后再添加一次酶，该反应并未延长。钾离子/氢离子反应的特点是在低酶活性（每毫升2×10⁻³单位）时达到饱和，并且受到质子载体羰基氰化物间氯苯腙的抑制，且与由细胞壁结构损伤导致的膜渗漏无关。酶诱导的总钾离子损失和氢离子摄取量是丁香假单胞菌豌豆致病变种诱导量的四分之一到三分之一，并且不会降低细胞活力。这些结果表明，果胶酸裂解酶在烟草中诱导的钾离子外流/氢离子内流反应与丁香假单胞菌豌豆致病变种在过敏反应中诱导的反应相似，但持续时间更短。因此，果胶酸裂解酶或其他细胞壁降解酶可能会影响过敏反应的诱导。
