蛋白激酶C同工酶分子结构及功能研究进展

蛋白激酶Ｃ（ＰＫＣ）是至少包括１１种亚型在内的丝／苏氨酸蛋白激酶家族,可分为传统型（ｃＰＫＣｓ）、新型（ｎＰＫＣｓ）、非典型（ａＰＫＣｓ）和ＰＫＣ－ｕ四大类。各ＰＫＣ亚型在ＡＴＰ结合位点、磷脂酰基转移位点、假性底物位点、佛波酯结合位点的氨基酸序列既高度保守又有变异。ＰＫＣ在机体内分布和作用十分广泛,本文主要介绍了ＰＫＣ在肿瘤形成、侵润和转移及肿瘤耐药性产生,调节造血干／祖细胞定向分化成熟,以及激素     

同工酶与桑品种遗传变异的关系

通过以冬芽为材料,对７６８１桑进行过氧化物酶,细胞色素氧化酶酶谱分析,结果表明７６８１桑是亲本体细胞融合的真杂种;     

Glutamine synthetase isoenzymes, oligomers and subunits from hairy roots of Beta vulgaris L. var. lutea

A cytosolic and a plastidic isoenzyme of glutamine synthetase (GS; EC 6.3.1.2) were separated from hairy roots of Beta vulgaris L. var. lutea. The predominant activity was that of cytosolic GS 1; the relative proportion of plastidic GS 2 activity changed, however, depending on the growth conditions. Maximum activity of both isoenzymes was measured after growth with NO⁻ ₃ as the major N-source. Growth with NH⁺ ₄ as the sole N-source or growth in constant darkness resulted in a significant decrease in GS 1 activity, whereas GS 2 activity was much less effected and thus contributed as much as 25% of total root GS activity. The isoenzymes GS 1 and GS 2 were active both in the octameric and tetrameric states. Both oligomers of GS 2 and octameric GS 1 were active under all growth conditions applied whereas tetrameric GS 1 was not active when the roots were grown under light-dark changes with NO⁻ ₃ as the major N-source. The molecular masses of the subunits were identical for both isoenzymes. Glutamine synthetase 1 was composed of up␣to four different 38-kDa subunits and two different 41-kDa subunits; GS 2 was assembled from one type of 38-kDa subunit and one type of 41-kDa subunit. The GS␣2 subunits were most probably identical to two of the GS␣1 subunits. The subunit composition of GS 1, but not of GS 2, changed depending on the growth conditions of the roots. Changes in GS 1 subunit composition were correlated with changes in GS 1 activity. The different growth conditions induced the specific assembly of different GS 1 isoenzymes which could, however, not be separated by anion-exchange chromatography but became evident only after two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Received: 30 May 1997 / Accepted: 28 August 1997     

Entamoeba histolytica: Virulence enhancement of isoenzyme-stable parasites

Pathogenic Entamoeba histolytica isolated from patients with clinical amoebiasis can be differentiated from nonpathogenic E. histolytica obtained from asymptomatic carriers on the basis of the electrophoretic pattern of their isoenzymes. Virulence of different strains of axenically grown trophozoites of Entamoeba histolytica, as determined by various laboratory tests, such as damage to tissue culture monolayers, or their ability to cause an hepatic abscess in a hamster, are known to vary considerably. Reassociation of trophozoites of strain HK-9 with certain Escherichia coli strains for short periods of time markedly augmented their virulence, as tested by the above-mentioned methods. The bacterial association, however, did not cause any change in the electrophoretic pattern of amoebic isoenzymes (zymodeme).     

姜黄属植物过氧化物酶同工酶的研究

用聚丙烯酰胺凝胶电泳分析姜黄属14种(28个样品)植物的过氧化物酶同工酶。结果表明属内种间有明显的酶谱差异,各种都有特征酶谱。根据酶谱特征及酶谱距离,结合根茎颜色,可把14个种分成三群:第一群,根茎黄色至深红色,有姜黄、毛姜黄、郁金、印尼莪术、C.petiolata和C.sP.(2);第二群,根茎灰白色,有广西莪术、大莪术和温郁金;第三群,根茎浅黄而间淡蓝色或深蓝色,有莪术、顶花莪术、细莪术、C.aeruginosa及C.zedoaria。研究结果还表明:1.国产莪术的酶谱与从美国引入的C.zedoaria和C.aeruginosa均不相同,而与引自新加坡的C.Phaeocaulis一致;2.不同形态的广西莪术具有完全一致的酶谱;3.温郁金与郁金的酶谱有差异。     

Detection of elastase activity with a zymogram method after isoelectric focusing in polyacrylamide gel

A zymogram method for detecting elastase activity following isoelectric focusing in polyacrylamide gel is described. After enzyme activity has been visualized, the gel itself is available for protein staining and for analysis in sodium dodecyl sulfate-polyacrylamide gel electrophoresis in second dimension. The zymogram method is suitable for detecting microgram amounts of elastase and has one step only. It can be used with the purified enzyme as well as with crude extracts of tissue containing elastases showing activity toward succinyl-(Ala)₃-p-nitroanilide. By this method a major component of elastase in both porcine and rat pancreas was detected. In addition, two forms of elastase with isoelectric points of 8.2 and 8.8, respectively, were identified in rat leukocyte extracts.     

Detection of cellulase activity in polyacrylamide gels using Congo red-stained agar replicas

Bands that have cellulolytic activity are visualized after polyacrylamide gel electrophoresis by laying the slab gel on top of a thin sheet of 2% agar containing 0.1% carboxymethylcellulose. After a suitable incubation time, zones of carboxymethylcellulose hydrolysis are revealed by staining the agar replica with Congo red.     

L615白血病鼠胸腺和脾脏淋巴细胞脱氢酶同工酶的研究

应用聚丙烯酰胺凝胶电泳法对比研究了纯系６１５鼠和Ｌ６１５可移植性淋巴细胞型白血病鼠胸腺和脾脏淋巴细胞的葡萄糖－６－磷酸脱氢酶同工酶（ＥＣｌ．１．１．４９,Ｄ－葡萄糖－６－磷酸：ＮＡＤＰ氧化还原酶,Ｇ６ＰＤ）和乳酸脱氢酶同工酶（ＥＣｌ．１．１．２７,Ｌ－乳酸：ＮＡＤ氧化还原酶,ＬＤＨ）。并应用定量细胞化学法对ＬＤＨ和６ＰＤ全酶活性进行了测定。结果：在Ｌ６１５白血病鼠胸腺淋巴细胞中（白血病细胞占４０％）,Ｇ６ＰＤ同工酶谱显示异常,全酶活性明显增高、ＬＤＨ同工酶谱及全酶活性未发生明显变化。Ｌ６１５白血病鼠脾脏淋巴细胞中（白血病细胞占８４％）,Ｇ６ＰＤ和ＬＤＨ同工酶谱均显示异常,同时全酶活性也明显增强。提示：Ｇ６ＰＤ对白血病细胞的恶性增殖和浸润似乎更为敏感。     

湛江红橙准分子激光处理的诱变效应研究

准分子激光对湛江红橙无性繁殖材料（枝条）辐照的结果表明：在适当剂量辐照下,可以产生少核或无核的变异,并且可改善橙果的风味品质。同工酶的分析也显示出,准分子激光已能引起湛江红橙的遗传变异。