Evolution of peroxisomal enzymes-Lost organization of uric acid degrading enzymes during animal development-

嘌呤降解的最终产物因物种不同而不同。嘌呤降解的最终产物在人类、类人灵长类动物和新的威尔猴子中是尿酸，在灵长类和旧大陆猴子以外的哺乳动物中是尿囊素，在一些硬骨动物中是尿囊素酶，在鱼类和两栖动物中是尿囊酸酶尿素，在许多无脊椎动物中是氨水。嘌呤在所有动物物种中降解为尿酸盐是常见的，而在高等动物中尿酸的降解要少得多。我们曾报道，在海洋鱼类中，嘌呤降解为尿酸的酶位于胞浆中，而尿酸降解为尿素的酶位于过氧化体中。这表明，在嘌呤降解过程中，过氧化物酶在进化过程中已经丢失。尿囊素酶和尿囊酸酶在鱼类肝脏中是不同的蛋白质，而在两栖动物肝脏中这两种酶是由一个复合体组成的。我们研究了两栖类尿囊素酶-尿囊酸酶复合体的形成机制，并在Hig…中丢失。(1)牛蛙(Rana Catesbeiana)尿囊素酶基因全长2112个碱基对，含有一个1449个碱基的开放阅读框，对应一个483个残基的蛋白质(53,296 Da)(2)。用聚合酶链式反应进行扩增，DNA测序仪进行测序。(3)在咸水鱼肝中，嘌呤降解的最终产物是尿素和乙醛。丙氨酸：乙醛酸氨基转移酶可将乙醛酸转化为甘氨酸，以重新利用嘌呤碳。(4)普遍认为，在哺乳动物进化过程中，所有尿囊素降解酶都丢失了。令人惊讶的是，在哺乳动物组织中发现了尿苷乙醇酸裂解酶。大鼠尿苷乙二酸酯酶的表观Km(17 MM)远高于鱼肝尿苷乙二酸酯裂解酶(0.33 mM)。哺乳动物在体内已经失去了这种功能，因为在进化过程中，尿苷乙醇酸的Km升高。(5)牛蛙过氧化氢酶基因全长1636个碱基对，含有1584个碱基的开放阅读框，编码528个氨基酸。(59871)更少

End products of purine degradation vary from species to species. The end product of purine degradation is urate in humans, hominoid primates and new would monkeys, allantoin by uricase in mammals other than primates and old world monkeys, allantoate by allantoinase in some teleosts, urea by allantoicase in fish and amphibians and ammonia in many invertebrates.The degradation of purines to urate is common to all animal species, while the degradation of urate is much less complete in higher animals. We have reported that in marine fish, the degrading enzymes of purines to urate are located in the cytosol, while the degrading enzymes of urate to urea are located in the peroxisomes. This shows that in purine degradation, peroxisomal enzymes have been lost during evolution. Allantoinase and allantoicase are different proteins in fish liver, whereas the two enzymes from a complex in amphibian liver. We examined the mechanism to form amphibian allantoinase-allantoicase complex and lose in hig … More her animals during animal evolution.(1).The cDNA encoding bullfrog (Rana Catesbeiana) allantoinase is 2112 base pairs in length containing a 1449-base pair open reading frame which corresponds to a 483-residue protein.(53,296 Da) (2).We did the cloning of lambda gt 11 cDNA endoding zebra fish allantoinase. The cDNA was applified with PCR and sequenced with DNA sequencer. (3).In saltwater fish liver, the end products of purine degradation are urea and glyoxylate. Glyoxylate may be converted to glycine by alanine : glyoxylate aminotransferase for the reutilization of purine carbons. (4).It is generally accepted that all of the allantoin-degrading enzymes were lost during mammalian evolution. Surprisingly, ureidoglycollate lyase has been found in a mammalian tissue. The apparent Km (17 mM) of the rat enzyme for ureidoglycollate was much higher than (0.33 mM) of fish-liver ureidoglycollate lyase. Mammals have lost the function in vivo by elevating the km for ureidoglycollate during evolution. (5).cDNA encoding bullfrog catalase is 1636 base pairs in length containing a 1584 bases of an open reading frame that encoded 528 amino acids. (59871) Less