Purification of cyclic 3’,5’-nucleotide phosphodiesterase of bovine brain cerebrum resulted in partial loss of activity, due to dissociation of an activator (or cofactor) from the enzyme. A systematic study showed that as purification proceeded, the activator was removed from phosphodiesterase in a stepwise fashion. Fractions representing phosphodiesterase at different stages of purification co...

this article is an attempt to survey the contraction and cancellation of the reuter’s agreement as a one-sided approach and from special perspective, by using minimalistic ideology and with emphasis on multi-sided and various reasons and factors effective in the process of this contract.  on the basis of this research, in this contraction, different factors came together and augmented one anoth...

neonate ruminants possess little cell-wall and starch degrading enzyme activity. importantly, early establishment of fibrolytic, amylolytic, and proteolytic capacities is influential for the early expansion of the reticulorumen epithelia. such an early development in reticulorumen fermentation will enable a timely hepatic adaptation to volatile fatty acids assimilation. the early nutrient relea...

Complex U is composed of orotate phosphoribosyltransferase (EC 2.4.2.10) and orotidine-5’-phosphate decarboxylase (EC 4.1.1.23), the last two enzymes of the de nouo pathway for pyrimidine biosynthesis. Since the two enzymes have proved inseparable so far, the equilibrium constant for the phosphoribosyltransferase activity has been determined under conditions where the decarboxylase activity was...

Chloroplasts contain the enzyme glutamine synthetase. Formation of glutamine by isolated chloroplasts is light-dependent and requires an intact outer envelope. Addition of exogenous glutamic acid, as well as nitrogen donors such as nitrite or ammonium, stimulate the synthesis of this amide. Photosynthetic generation of ATP satisfies the light requirement of glutamine synthesis. The process is s...

An arylamine N-acetyltransferase (NAT) responsible for the N acetylation of exogenous 3-amino-4-hydroxybenzoic acid in Streptomyces griseus was identified and characterized. This enzyme was distinct from other eukaryotic and bacterial NATs in that it acetylated various 2-aminophenol derivatives more effectively than it acetylated 5-aminosalicylic acid, and thus it may be involved in the metabol...

Deoxyadenosine is a toxic substrate of adenosine deaminase and accumulates as deoxyATP in cells of patients deficient in that enzyme. However, it is unclear which of the deoxyadenosine phosphorylating enzymatic activities is responsible for this accumulation of deoxyATP in humans. From a human lymphoblastoid cell line, WI-LP, mutants deficient in various nucleoside kinase enzymes have been isol...

The ability of ruminants to convert plant biomass unsuitable for human consumption into meat and milk is of great societal and agricultural importance. However, the efficiency of this process is largely dependent on the digestibility of plant cell walls. Supplementing ruminant diets with exogenous enzymes has the potential to improve plant cell wall digestibility and thus the efficiency of feed...

the effects of drought stress and exogenous abscisic acid on the expression of ribulose-1, 5-bisphosphate carboxyiase/oxygenase activase (rubisco activase) were examined in wheat (triticum aestivuml.). in response to water stress and abscisic acid, both the levels of endogenous abscisic acid and rubiscoactivase increased in the leaves. immunoblot analysis showed that both drought stress and abs...