Bell E, Malmberg R L
Department of Botany, University of Georgia, Athens 30602.
Mol Gen Genet. 1990 Dec;224(3):431-6. doi: 10.1007/BF00262438.
Arginine decarboxylase is the first enzyme in one of the two pathways of putrescine synthesis in plants. We purified arginine decarboxylase from oat leaves, obtained N-terminal amino acid sequence, and then used this information to isolate a cDNA encoding oat arginine decarboxylase. Comparison of the derived amino acid sequence with that of the arginine decarboxylase gene from Escherichia coli reveals several regions of sequence similarity which may play a role in enzyme function. The open reading frame (ORF) in the oat cDNA encodes a 66 kDa protein, but the arginine decarboxylase polypeptide that we purified has an apparent molecular weight of 24 kDa and is encoded in the carboxyl-terminal region of the ORF. A portion of the cDNA encoding this region was expressed in E. coli, and a polyclonal antibody was developed against the expressed polypeptide. The antibody detects 34 kDa and 24 kDa polypeptides on Western blots of oat leaf samples. Maturation of arginine decarboxylase in oats appears to include processing of a precursor protein.
精氨酸脱羧酶是植物中腐胺合成两条途径之一的首个酶。我们从燕麦叶片中纯化了精氨酸脱羧酶，获得了其N端氨基酸序列，然后利用这些信息分离出了一个编码燕麦精氨酸脱羧酶的cDNA。将推导的氨基酸序列与来自大肠杆菌的精氨酸脱羧酶基因的序列进行比较，发现了几个可能在酶功能中起作用的序列相似区域。燕麦cDNA中的开放阅读框（ORF）编码一个66 kDa的蛋白质，但我们纯化的精氨酸脱羧酶多肽的表观分子量为24 kDa，并且由ORF的羧基末端区域编码。编码该区域的cDNA的一部分在大肠杆菌中表达，并针对表达的多肽制备了多克隆抗体。该抗体在燕麦叶片样品的蛋白质免疫印迹上检测到34 kDa和24 kDa的多肽。燕麦中精氨酸脱羧酶的成熟似乎包括前体蛋白的加工。
