CYP83B1 Is the Oxime-metabolizing Enzyme in the Glucosinolate Pathway in \u3ci\u3eArabidopsis\u3c/i\u3e

CYP83B1 from Arabidopsis thaliana has been identified as the oxime-metabolizing enzyme in the biosynthetic pathway of glucosinolates. Biosynthetically active microsomes isolated from Sinapis alba converted p-hydroxyphenylacetaldoxime and cysteine into S-alkylated p-hydroxyphenylacetothiohydroximate, S-(p-hydroxyphenylacetohydroximoyl)-L-cysteine, the next proposed intermediate in the glucosinolate pathway. The production was shown to be dependent on a cytochrome P450 monooxygenase. We searched the genome of A. thaliana for homologues of CYP71E1 (P450ox), the only known oxime-metabolizing enzyme in the biosynthetic pathway of the evolutionarily related cyanogenic glucosides. By a combined use of bioinformatics, published expression data, and knock-out phenotypes, we identified the cytochrome P450 CYP83B1 as the oxime-metabolizing enzyme in the glucosinolate pathway as evidenced by characterization of the recombinant protein expressed in Escherichia coli. The data are consistent with the hypothesis that the oxime-metabolizing enzyme in the cyanogenic pathway (P450ox) was mutated into a “P450mox” that converted oximes into toxic compounds that the plant detoxified into glucosinolates

A Synapse-State Theory of Mental Life

Introduction: `The problem of understanding behavior is the problem of understanding the total action of the nervous system, and vice versa. ... The central problem with which we must find a way to deal can be put in two different ways. Psychologically, it is the problem of thought: some sort of process that is not fully controlled by environmental stimulation and yet cooperates closely with that stimulation. From another point of view, physiologically, the problem is that of the transmission of excitation from sensory to motor cortex. ... In the chapters that follow this introduction I have tried to lay a foundation for such a theory. ... In outline, the conceptual structure is as follows: Any frequently repeated, particular stimulation will lead to the slow development of a "cell-assembly," a diffuse structure comprising cells in the cortex and diencephalon (and also, perhaps, in the basal ganglia of the cerebrum), capable of acting briefly as a closed system, delivering facilitatio

Computing : a human activity

xxvi, 630 p. ; 23 cm