This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (22) Citing Articles via Google Scholar Google Scholar Articles by Glenn, E. Articles by Maretzki, A. Search for Related Content PubMed PubMed Citation Articles by Glenn, E. Articles by Maretzki, A. Agricola Articles by Glenn, E. Articles by Maretzki, A.

Articles

Properties and Subcellular Distribution of Two Partially Purified Ornithine Transcarbamoylases in Cell Suspensions of Sugarcane ¹

Andrew Maretzki^b

^a Department of Botany, University of Hawaii Honolulu, Hawaii 96822, Hawaiian Sugar Planters' Association Experiment Station, Aiea, Hawaii 96701

The spatially separated forms of ornithine transcarbamoylase (EC 2.1.3.3) of different molecular weights coexist in sugarcane (Saccharum sp.). The smaller form of the enzyme (mol wt 79,000) appears to be cytoplasmic, while a larger form (mol wt 224,000) sedimented with mitochondria. The Km of the cytoplasmic enzyme for ornithine was 3.11 mM, while the enzyme in the mitochondrial fraction had a Km of 0.50 mM for this substrate; both enzymes had similar affinity for carbamoyl phosphate (0.12 mM). Characteristics of the smaller ornithine transcarbamoylase are in keeping with a predominantly catabolic function, those of the enzyme which sediments with mitochondria, with an anabolic function. Only the mitochondrial enzyme was regulated in vivo by exogenous arginine.