isoleucine plus valine

locus: ilv

locus_name: isoleucine plus valine

organism_type: B

chromosome_number:

chromosome_side:

link_group:

cultural_requirements: Three loci specify enzymes that catalyze corresponding steps in the parallel biosynthetic pathways of isoleucine and valine (Fig. 15). These enzymes are located in the mitochondria (79, 597 and references therein) and may indirectly affect electron transport (79). The enzymes may be in an aggregate; for a review, see reference 237. The requirements are for both amino acids. A ratio of 20-30% isoleucine to 80-70% valine is optimal (99). At least some ilv mutants are inhibited by norleucine, norvaline, phenylalanine (99), or tryptophan (J.F. Leslie, personal communication). Enzyme production in response to end-product-derived signals depends on the leu-3+ product and alpha-isopropylmalate. In leu-3+ strains, threonine deaminase production is repressed as a function of available isoleucine, acetohydroxyacid synthetase is repressed as a function of valine, and isomeroreductase and dihydroxyacid dehydratase are repressed as a function of isoleucine and leucine. In the absence of effective leu-3product, alpha-IPM, or both, enzyme production is repressed even under severe end product limitation. (771) Formerly called iv.Biosynthetic pathways of isoleucine, valine, and leucine, showing sites of gene action (22, 136. 426, 549, 727. 854, 1112). Isoleucine and valine are synthesized along parallel pathways catalyzed by common enzymes. The leucine precursors alpha- and beta-isopropylmalate were formerly called beta-OH-beta-carboxyisocaproate and alpha-OH-beta-carboxyisocaproate, respectively.

enzyme_id:

anid_name:

near_l:

near_r:

neu_name:

supplement: isoleucine and valine

image_url:

Strains

FGSC #	Reporting Genes	Species
FGSC #4633	This strain is not available T(IIL;VL)AR30 T(IIR;VR)ALS154 arg-5 fl ilv acr-3	Neurospora crassa
FGSC #4634	This strain is not available T(IIL;VL)AR30 T(IIR;VR)ALS154 arg-5 fl ilv acr-3	Neurospora crassa

References

Authors	Title	Year
Altimiller, D. H. , and R. P. Wagner.	Deficiency of dihydroxy acid dehydratase in the mitochondria of iv-1 mutants of N. crassa.	1970
Bergquist, A. , E. A. Eakin, R. T. Eakin, and R. P. Wagner,	Growth, respiratory, and cytochrome characteristics of certain of theisoleucine-valine mutants of N. crassa.	1974
Bonner, D. M. , E. L. Tatum, and G. W. Beadle.	The genetic control of biochemical reactions in Neurospora:a mutant strain requiringisoleucine and valine.	1943
Caroline, D. F. , R. W. Harding, H. Kuwana, T. Satyanarayana, and R. P. Wagner.	The iv-3 mutants of N. crassa. II. Activity ofacetohydroxy acid synthetase.	1969
Gross, S. R.	The regulation of synthesis of leucine biosynthetic enzymes in Neurospora.	1965
Kinsey, J. A.	Isoleucineless mutants of Neurospora lacking threonine deaminase activity.	1970
Leiter, E. H. , D. A. LaBrie, A. Bergquist, and R. P Wagner.	In vitro mitochondrial complementation in Neurospora crassa.	1971
Myers, J. W. , and E. A. Adelberg.	The biosynthesis of isoleucine and valine. I. Enzymatic transformation of the dihydroxy acid precursors to the keto acid precursors.	1954
Olshan, S. R. , and S. R. Gross.	Role of the leu-3 cistron in the regulation of the synthesis of isoleucine and valine biosyntheticenzymes of Neurospora.	1974
Radhakrishnan, A. N. , R. P. Wagner, and E. E. Snell.	Biosynthesis of valine and isoleucine. III. alpha-keto-beta-hydroxy acidreductase and alpha-hydroxy-beta-keto acid reductoisomerase.	1960
Wagner, R. P. , A. Bergquist, T. Barbee, and K. Kiritani.	Genetic blocks in the isoleucine-valine pathway of Neurospora crassa.	1964