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A second distinct chlorophyll a – protein complex has been resolved in extracts of maize mesophyll chloroplasts. Resolution was accomplished through modified incubation and electrophoresis and through the use of a mutant deficient of chlorophyll b. This complex, complex IV, has an electrophoretic mobility similar to that of the light-harvesting chlorophyll a/b – protein and chlorophyll a is its major pigment component. Carotenoids are probably also present in this complex. Evidence to date indicates a correlation between the presence of complex IV and photosystem II.

Chlorophyll–protein complexes of thylakoid membranes from rye plants (Secale cereale L. cv. Puma) grown at warm and cold-hardening temperatures were investigated by gel electrophoresis. Complex IV from cold-grown tissue was detectable in the presence of dodecyl sulfate if and only if solubilization and electrophoresis were performed at 4 °C, whereas complex IV from warm-grown material was detectable if membrane solubilization and electrophoresis were performed at either 4 or 23 °C in the presence of dodecyl sulfate. In the presence of octyl-β-D-glucopyranoside, the chlorophyll–protein complexes from cold-grown tissue were less stable at 23 °C than those from warm-grown tissue. Regardless of the detergent used, there was always more oligomer of the light-harvesting complex present in samples prepared from thylakoid membranes of warm-grown tissue than those from membranes of cold-grown tissue. It is concluded that the pigment–protein interaction in those complexes associated with photosystem II and the light-harvesting chlorophyll a/b – protein complex has been altered upon growth and development at cold-hardening temperatures.

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The effects of simple-carbohydrate (CHO)- and complex-CHO-rich diets on skeletal muscle glycogen content were compared. Twenty male marathon runners were divided into four equal groups with reference to dietary consumption: depletion/simple, depletion/complex, nondepletion/simple, and nondepletion/complex. Subjects consumed either a low-CHO (15% energy [E] intake), or a mixed diet (50% CHO) for 3 days, immediately followed by a high-CHO diet (70% E intake) predominant in either simple-CHO or in complex-CHO (85% of total CHO intake) for another 3 days. Skeletal muscle biopsies and venous blood samples were obtained one day prior to the start of the low-CHO diet or mixed diet (PRE), and then again one day after the completion of the high-CHO diet (POST). The samples were analysed for skeletal muscle glycogen, serum free fatty acids (FFA), insulin, and lactate and blood glucose. Skeletal muscle glycogen content increased significantly (p less than 0.05) only in the nondepletion/simple group. When groups were combined, according to the type of CHO ingested and/or utilization of a depletion diet, significant increases were observed in glycogen content. Serum FFA decreased significantly (p less than 0.05) for the nondepletion/complex group only, while serum insulin, blood glucose, and serum lactate were not altered. It is concluded that significant increases in skeletal muscle glycogen content can be achieved with a diet high in simple-CHO or complex-CHO, with or without initial consumption of a low-CHO diet.