摘要
从杜氏盐藻分离得到的二羟丙酮还原酶能专一性地催化二羟丙酮和甘油之间的可逆反应。酶催化二羟丙酮还原及甘油氧化的最适 PH分别为7.5和9.0;藻细胞经高渗处理,其甘油含量增加,酶催化甘油合成的活性比处理前提高120％,且大于其催化甘油转化的活性;藻细胞经低渗处理,其甘油含量减少,酶催化甘油转化的速率比处理前提高32％,暗示二羟丙酮还原酶在杜氏盐藻渗透调节过程中是甘油合成或转化的一个关键酶。
A NADP^+-dependent dihydroxy-acetone reductase isolated from Dunaliel-la salina is an enzyme which catalyzesspecifically the reversible reaction be-tween dihydroxyacetone and glycerol.The pH optima for dihydroxyacetonereduction and for glycerol oxidationwere 7. 5 and 9. 0, respectively.NADPH was oxidised by the enzymeduring dihydroxyacetone reduction,and the rate was 21. 0 umol mg^(-1) pro-tein min^(-1); NADP^+ was reduced dur-ing glycerol oxidation, and the ratewas 28. 2 umcl mg^(-1) protein min^(-1). When algal cells were subjected toa hyperosmotic shock from a solutionof 1. 5 mol/L to 3. 5 mol/L of NaC1,the intracellular glycerol content in-creased by 2. 0 mol/L. The dihydroxy-acetone reductase activity in glycerolsynthesis was higher than that of glyc-erol conversion and increased by120%. After a hypoosmotic treatmentfrom a solution of 3 mol/L to a solu-tion of 1 mol/L of NaC1, the intracel-lular glycerol content decreased by 2. 1mol/L, and the catalytic activity ofthe enzyme for glycerol conversion in-creased by 32%. It is suggested thatdihydroxyacetone reductase is a keyenzyme in glycerol synthesis and con-version in the osmoregulation ofDunaliella salina.
关键词
杜氏盐藻
二羟丙酮
还原酶
渗透
Dunaliella salina
dihydroxyacetone reductase
osmotic stress
glycerol synthesis
glycerol conversion
