Highly active mechanism

The metabolism of apiose in plants has not been investigated extensively. It has been suggested80 that apiose could give rise to simple terpenes by condensation and reduction. Incubation of [ -,4C]apiose in parsley plants resulted in negligible, but unspecified, amounts of carbon-14 incorporated into apiin.66 The specific activity of the [ -14C]apiose administered was low (5 X 105 d.p.m./jumole) for this reason, the data suggested only that no highly active mechanism is available in parsley for the metabolism of this branched-chain sugar. 

About Fei xO Based Catalysts and Their Highly Active Mechanism... 

The sulfated compounds MM 13902 (3, n = (5) and MM 17880 (4) are also broad-spectmm agents, but not as potent as thienamycia and all lack any significant activity against Pseudomonas (73). Many carbapenems are excellent inhibitors of isolated P-lactamases, particularly the olivanic acid sulfoxide MM 4550 (3, n = 1) (3). The possible mechanism of action of the carbapenems as inhibitors of P-lactamases has been discussed in some detail (74). Other carbapenems such as PS-5 (5) (75), the carpetimycins (76), asparenomycins (77), and pluracidomycins (8) are all highly active as antibiotics or P-lactamase inhibitors. The parent nucleus itself (1, X = CH2) is intrinsically active, but chemically unstable (9). 

The detailed mechanism of battery electrode reactions often involves a series of chemical and electrochemical or charge-transfer steps. Electrode reaction sequences can also include diffusion steps on the electrode surface. Because of the high activation energy required to transfer two electrons at one time, the charge-transfer reactions are beheved to occur by a series of one electron-transfer steps illustrated by the reactions of the 2inc electrode in strongly alkaline medium (41). 

This particular reaction has quite a high activation energy, which suggests that a nonconcerted mechanism might be involved. An alternative explanation for the observed stereochemistry has been advanced. 

The question of the occurrence of cine or aryne substitution in some of these reactions has been raised but not answered adequately. The normal product, 2-methoxynaphthalene was shown to be formed from 2-chloronaphthalene and methoxide ion, and the normal 6- and 8-piperidinoquinolines were proved to be products of piperidino-debromination of 6- and 8-bromoquinolines, all in unspecified yield. More highly activated compounds were then assumed not to react via the aryne mechanism. Even if the major product had been characterized, the occurrence of a substantial or predominant amount of aryne reaction may escape notice when strong orientation or steric effects lead to formation of the normal displacement product from the aryne. A substantial amoimt of concurrent aryne reaction may also escape detection if it yields an amount of cine-substituted material easily removed in purification or if the entire reaction mixture is not chromatographed Kauffman and Boettcher have demonstrated that activated compounds such as 4-chloropyridine do indeed react partially via the aryne mechanism (Section I,C,1). 

The breakdown of the job into steps is based upon personal experience of the planner or from history or standard job plans. Depending upon the job and skill level of the craftsman, it may require one activity or one hundred. Highly skilled mechanics may require a higher degree of instruction in the plan or how to complete the job, as well as closer supervision and support during job execution. 

The high active tension and/or high active strain that occurs in muscle during lengthening contractions is believed to cause mechanical disruption of muscle fibers and connective tissue (Armstrong, 1984 Lieber and Friden, 1993). Activa-... 

Amidinate complexes of copper(I) and copper(II) have been found to catalyze the polymerization of carbodiimides. The copper catalysts are highly active even under air and oxygen. It was shown that the catalytic activity of an air-stable copper(II) amidinato complex is almost equal to that of reported air-sensitive titanium(IV) amidinate initiators. Scheme 225 illustrates the proposed reaction mechanism. ... 

In some resistant strains, both types of resistance mechanism have been shown to operate against the same insecticide. Thus, the PEG87 strain of the tobacco bud worm (Heliothis virescens) is resistant to pyrethroids on account of both a highly active form of cytochrome P450 and an insensitive form of the sodium channel (Table 4.3 and McCaffery 1998). 

The reaction shows a rather high activation energy of 32.0 kcal.mole . Speculation about the mechanism is worthless until more controlled experiments are performed, taking account of hydrolysis, the role of the reaction Fe(lI)+NH20H, etc. 

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