Factors Involved in in Vitro Stabilization of Nitrate Reductase from Cotton (Gossypium hirsutum L.) Cotyledons

Abstract
Experiments were conducted to determine if pretreatment of cotton (Gossypium hirsutum L.) plants resulted in differential in vitro stabilities of nitrate reductase (NR) activity. Although NR activity declines markedly during the second half of the daily light period, in vitro NR stability is not modified by time of harvest. Phenylmethylsulfonylfluoride, iodoacetamide, and N-ethylmaleimide do not influence in vitro NR stability, suggesting that serine or sulfhydryl proteases are not responsible for in vitro lability of NR from cotton cotyledons.