A method for the rapid determination of alkaline phosphatase with five cubic millimeters of serum

Plasma phosphatase was first determined by Martland (1925) and then by Kay (1930), using glycerophosphate and estimating the inorganic phosphate liberated at 370 C. at a specified pH and in a given time. The procedure has been variously modified and simplified by Jenner and Kay (1932), Bodansky (1933), Shinowara, Jones, and Reinhart (1942). Several substrates, other than glycerophosphate, have also been used, e.g., phenyl phosphate (with determination of either the liberated phenol, King and Armstrong, 1934, or phosphate, King, Abul-Fadl, and Walker, 1951), nitro-phenyl phosphate (by the colour of the liberated nitrophenol, Ohmori, 1937; King and Delory, 1939; Bessey, Lowry, and Brock, 1946), naphthyl phosphate (by determination of naphthol by a diazo method, Seligman, Chauncey, Nachlas, Manheimer, and Ravin, 1951), phenolphthalein phosphate (by the colour of alkaline phenolphthalein, Bray and King, 1943; Huggins and Talalay, 1945). Of the.se procedures, the Bodansky (glycerophosphate) and the King-Armstrong (phenyl phosphate) are perhaps the most widely used. King and Armstrong (1934) determined free phenol, liberated from phenyl phosphate by the phosphatase, by either the Folin and Ciocalteu (1927) phosphomolybdic reagent or by the diazo reaction, and preferred the former. Both procedures required the precipitation and removal of the plasma proteins subsequent to the hydrolysis of the substrate. In 1951 Grifols Lucas proposed a procedure for determination of the free phenol, which did not require removal of the proteins. This was based on the 4-amino-antipyrine reaction of Gottlieb and Marsh (1946). In this method the conditions under which enzymic hydrolysis is carried out are the same as in the King-Armstrong method, as modified by King (1951), the amino-antipyrine reagent (A.A.P.) being used to estimate the phenol liberated. 4-Amino-antipyrine reacts with certain phenolic substances in the presence of alkaline oxidizing agents to produce quinonoid substitution products. These give a red colour proportional to the phenol present, and can be determined colorimetrically. Grifols-Lucas found that A.A.P. does not react with plasma proteins, and their removal is unnecessary when phosphatases are estimated.

https://jcp.bmj.com/content/jclinpath/7/4/322.full.pdf

Estimation of Plasma Phosphatase by Determination of Hydrolysed Phenol with Amino-antipyrine

Significant advances have taken place in our knowledge of the enzymes involved in steroid hormone biosynthesis since the last comprehensive review in 1988. Major developments include the cloning, identification, and characterization of multiple isoforms of 3β-hydroxysteroid dehydrogenase, which play a critical role in the biosynthesis of all steroid hormones and 17β-hydroxysteroid dehydrogenase where specific isoforms are essential for the final step in active steroid hormone biosynthesis. Advances have taken place in our understanding of the unique manner that determines tissue-specific expression of P450aromatase through the utilization of alternative promoters. In recent years, evidence has been obtained for the expression of steroidogenic enzymes in the nervous system and in cardiac tissue, indicating that these tissues may be involved in the biosynthesis of steroid hormones acting in an autocrine or paracrine manner. This review presents a detailed description of the enzymes involved in the biosynthe...

https://www.researchgate.net/profile/Dale_Buck_Hales/publication/8144948_Overview_of_steroidogenic_enzymes_in_the_pathway_from_cholesterol_to_active_steroid_hormones/links/02e7e5249ac2529059000000.pdf

Overview of Steroidogenic Enzymes in the Pathway from Cholesterol to Active Steroid Hormones

This article summarizes all experimental facts concerning the cold denaturation of single-domain, multi-domain, and multimeric globular proteins in aqueous solutions with and without urea and guanidine hydrochloride. The facts obtained by various experimental techniques are analyzed thermodynamically and it is shown that the cold denaturation is a general phenomenon caused by the very specific and strongly termperature-dependent interaction of protein nonpolar groups with water. Hydration of these groups, in contrast to expectations, is favorable thermodynamically, i.e., the Gibbs energy of hydration is negative and increases in magnitude at a temperature decrease. As a result, the polypeptide chain, tightly packed in a compact native structure, unfolds at a sufficiently low temperature, exposing internal nonpolar groups to water. The reev-aluation of the hydration effect on the base of direct calorimetric studies of protein denaturation and of transfer of non-polar compounds into water leads to r...

Cold denaturation of proteins.

Publisher Summary This chapter reviews that the simplest way of accounting for the absorption spectrum of a protein is as the sum of the spectra of its components. This gives results which are often good approximations to the observed protein spectrum. The assumption of additivity is basic for useful analytical applications of spectral measurements. It discusses that in another perspective, the failure of perfect additivity of the component absorptivities affords the possibility of obtaining structural information about proteins. The absorptivity of the peptide bond can change by as much as a factor of two with a change in the conformation of a peptide chain. Since the absorptivity of aromatic side chains is much less sensitive to environmental change, correspondingly, more sensitive techniques are required to measure the small changes which do occur. The nature and limitations of the structural information resulting from both peptide-bond and side-chain absorption are discussed. Absorption spectra can occasionally be a useful tool in the identification of unusual structural features in proteins and polypeptides. Several such applications are also explained in this chapter.

Paul Talalay

Papers

Enzymic analysis of steroid hormones.

Chromogenic substrates; phenolphthalein glucuronic acid as substrate for the assay of glucuronidase activity.

Purification of a 17β-Hydroxysteroid Dehydrogenase of Human Placenta and Studies on Its Transhydrogenase Function

Sodium phenolphthalein phosphate as a substrate for phosphatase tests

INDUCTION AND PURIFICATION OF α- AND β-HYDROXYSTEROID DEHYDROGENASES