Santana C, Segura D, Sánchez S
Departamento de Biotecnología, Universidad Nacional Autónoma de México, D.F. Mexico.
Rev Latinoam Microbiol. 1994 Apr-Jun;36(2):139-58.
The microbial secondary metabolites are compounds with a wide range of chemical structures, produced mainly by actinomycetales and some fungi, usually in the late growth phase. Although a high proportion of this metabolites are antibiotics, there are also examples with pigment, herbicide and surfactant properties. Its function has been correlated to bacterial pathogenicity and cellular differentiation, however, properties dealing with chelation, hormonal and antitumor activities as well as nutritional reserve have been also reported. As in other examples of cellular compounds, the secondary metabolites are produced from low molecular weight precursors. For this purpose, specific biosynthetic pathways are utilized and regulated by processes which generally affect either the activity or the synthesis of the enzymes involved in it. Considering the secondary metabolites apparently are dispensable compounds, there are difficulties to explain their existence from an evolutionary point of view. Explanations to their existence have gone from laboratory artifacts to those conferring them an adaptative value in the past. It seems that they were maintained due to selective advantages to the producer microorganisms and probably, their sometimes complex biosynthetic pathways, have emerged from primary metabolites and evolved later independently by random mutation, amplification and genetic transfer.
微生物次级代谢产物是一类化学结构广泛的化合物，主要由放线菌和一些真菌产生，通常在生长后期产生。虽然这类代谢产物中很大一部分是抗生素，但也有具有色素、除草剂和表面活性剂特性的例子。其功能与细菌致病性和细胞分化有关，然而，也有报道称其具有螯合、激素和抗肿瘤活性以及营养储备等特性。与其他细胞化合物的例子一样，次级代谢产物由低分子量前体产生。为此，利用特定的生物合成途径，并通过通常影响参与其中的酶的活性或合成的过程进行调节。考虑到次级代谢产物显然是可有可无的化合物，从进化的角度很难解释它们的存在。对它们存在的解释从实验室产物到过去赋予它们适应性价值的解释都有。它们似乎是由于对生产者微生物具有选择优势而得以保留，而且它们有时复杂的生物合成途径可能是从初级代谢产物中产生，后来通过随机突变、扩增和基因转移独立进化而来。
