Barbieri L, Valbonesi P, Bonora E, Gorini P, Bolognesi A, Stirpe F
Dipartimento di Patologia sperimentale dell'Università degli Studi di Bologna Via San Giacomo 14, I-40126 Bologna, Italy.
Nucleic Acids Res. 1997 Feb 1;25(3):518-22. doi: 10.1093/nar/25.3.518.
Ribosome-inactivating proteins (RIP) are a family of plant enzymes for which a unique activity was determined: rRNAN-glycosidase at a specific universally conserved position, A4324in the case of rat ribosomes. Recently we have shown that the RIP from Saponaria officinalis have a much wider substrate specificity: they are actually polynucleotide:adenosine glycosidases. Here we extend studies on substrate specificity to most known RIP: 52 purified proteins, both type 1 (single-chain) and type 2 (two chain, an enzymatic chain and a lectin chain) were examined for adenine release on various substrates including RNAs from different sources, DNA, and poly(A). All RIP depurinated extensively DNA and some released adenine from all adenine-containing polynucleotides tested. From experimental evidence the entire class of plant proteins, up to now called ribosome-inactivating proteins, may be classified as polynucleotide:adenosine glycosidases. The newly identified substrates may be implicated in the biological role(s) of RIP.
核糖体失活蛋白（RIP）是一类植物酶，其独特活性已被确定：在特定的普遍保守位置上的rRNA N - 糖苷酶，对于大鼠核糖体而言是A4324 。最近我们发现肥皂草中的RIP具有更广泛的底物特异性：它们实际上是多核苷酸：腺苷糖苷酶。在这里，我们将对底物特异性的研究扩展到大多数已知的RIP：检测了52种纯化蛋白，包括1型（单链）和2型（双链，一条酶链和一条凝集素链），以检测它们在各种底物上的腺嘌呤释放情况，这些底物包括来自不同来源的RNA、DNA和聚腺苷酸。所有RIP都能使DNA大量脱嘌呤，并且一些能从所有测试的含腺嘌呤多核苷酸中释放腺嘌呤。从实验证据来看，迄今为止被称为核糖体失活蛋白的整个植物蛋白类别，可能应归类为多核苷酸：腺苷糖苷酶。新确定的底物可能与RIP的生物学作用有关。
