McGaw BA, Horgan R. Cytokinin oxidase fromZea mays kernels andVinca rosea crown-gall tissue.
PLANTA 1983;
159:30-7. [PMID:
24258083 DOI:
10.1007/bf00998811]
[Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/1983] [Accepted: 05/05/1983] [Indexed: 05/11/2023]
Abstract
Cytokinin oxidase has been partially purified from matureZea mays kernels and fromVinca rosea corwn-gall tissue. The molecular weights of the two enzymes, determined by gel filtration, are very different: 94,400 (±10%) forZ. mays and 25,100 (±10%) forV. rosea. Specificity studies have been performed using a large number of synthetic and naturally occurring cytokinins. Only a small number of these compounds serve as substrates and both enzymes exhibit similar substrate specificity. In agreement with other workers, a Δ(2) double bond in the N(6) side chain is essential for activity. The presence of glucosyl or ribosyl groups in the 7-or 9-position or an alanyl group in the 9-position of the purine moiety have little effect on their susceptibility to cytokinin oxidase, but O-glucosyl derivatives are resistant to oxidation. The relevance of these enzyme systems to studies on cytokinin metabolism and to the endogenous cytokinins is discussed.
Collapse