The amino acid composition of twice recrystallized pepsin (Worthington Biochemical Corporation) has been determined chromatographically on columns of Amberlite IR 120 resin. The results of the analyses obtained on four different preparations indicate a close agreement in their amino acid composition. Pepsin is unique in that it has a great predominance of acidic amino acids over basic ones. Mor...

Very few data are available concerning the amino acid content of mammalian sperm. The early work by Kossel (1) on the protamines of fish sperm and on the histones was primarily concerned with an attempt to elucidate the structure of the basic proteins. The basic proteins are, in general, characterized by a high arginine content. Zittle and O’Dell (2) have determined the methionine content of wh...

Several years ago it was suggested that the crystalline globulins of the seeds of some of the Cucurbitaceae might provide a substitute for edestin for many types of work because of the doubtful availability of hemp-seed for future investigations (I, 2). With the use of the recently developed microbiological methods for amino acid analysis, it is now possible to extend our knowledge of the compo...

The fundamental importance of human milk in infant nutrition makes it desirable to have available as complete information as possible on the amounts of amino acids contributed to the diet from this source (Williamson (l), Block and Bolling (2, 3), and Macy (4)). In the present study, hydrolysates of human milk have been analyzed by ion exchange chromatography (Moore and Stein (5)) as applied in...

The recent finding (1, 2) that part of the enolase molecule can be removed by digestion with leucine aminopeptidase or carboxypeptidase without change in enzymic activity has prompted a detailed study of the relation between structure and activity in this enzyme. As a basis for such investigations it is necessary to have a knowledge of the principal features of enolase structure; the amino acid...

The physicochemical properties and amino acid composition of chymotrypsinogen B have been examined. The partial specific volume has been determined as 0.733 ml per g. From sedimentation velocity measurements, siO,, has been found to be 2.58 S at pH 3.0. At pH values above 4, the zymogen dimerizes as indicated by both sedimentation velocity and approach to sedimentation equilibrium measurements....

Among the properties of ribonuclease which make the protein particularly suitable for structural studies are its low molecular weight and its availability in chromatographically homogeneous form (2). Studies on the chemical structure of the enzyme have been inaugurated by Anfinsen, Redfield, Choate, Page, and Carroll (3) and are also being pursued in this laboratory (1). As complete information...

Introduction Conclusions References

Investigations of the association between an individual's habitual amino acid intake and several types of health outcome require a comprehensive amino acid composition database. The lack of a database of the amino acid content of foods routinely consumed makes estimating daily amino acid intake difficult. The aim of this study was to develop an amino acid database for use in epidemiological stu...

Amino acid composition of proteins can be modelled by both selectional and mutational pressures. The influence of selection is related with functional and structural requirements on proteins, whereas mutations modify directly nucleotide composition of protein coding sequences. To study the influence of these pressures on amino acid composition and its dependence from evolutionary relationships ...